“Fight the Landlord” is one of the most popular card games in China. The name comes from the 1950s, when the Chinese Communist Party confiscated property from landowners, often violently, in the name of the masses.

As many as two million people were killed. China’s state-controlled media is playing a new game of “Fight the Landlord,” and its target is one of the biggest landlords in the world: the 91-year-old Hong Kong billionaire Li Ka-shing.

Hong Kong’s summer of protests stems mainly from sky-high housing costs, China’s media argues, and Mr. Li and other local real estate tycoons should be held responsible. “In the current chaotic situation in Hong Kong, many young people are venting their dissatisfaction with high housing prices and expensive rents at the government,” said an official commentary by the party’s Central Political and Legal Affairs Commission, which oversees China’s police and courts.

“They’re probably blaming the wrong target.” The return of “Fight the Landlord” lays bare the Communist Party’s shifting attitudes toward the business world. Hong Kong’s property tycoons were once big beneficiaries of an unspoken pact between Beijing and business: They could wheel and deal as they liked, so long as they helped China achieve its economic dreams and left the politics to the Communist Party.

Today, as the party tightens its grip over daily Chinese life, business has become another tool for control. Business leaders who aren’t sufficiently loyal can suddenly find themselves at risk. And in Hong Kong, where companies operate under a different set of laws but still depend on the mainland for their profits, China’s state media is increasingly willing to threaten or humiliate any business leader who stands in the way.

The party’s growing reach raises questions about the future of people like Mr. Li — and, by extension, of all of Hong Kong. Mr. Li was a consummate player of the old game, cultivating ties with Beijing’s most powerful leaders even as he increased his wealth. But under Xi Jinping, China’s top leader, the party has demanded absolute loyalty, eliminating some of the gray areas where business in Hong Kong once stood.

“One of the biggest characteristics of Mr. Xi’s ruling style is that he’s not interested in uniting different interest groups,” said Leung Man-tao, a Hong Kong writer and commentator who has big followings in both the mainland and Hong Kong.

“He can’t see the value of gray areas. He wants absolute loyalty.” In the mainland, the party has taken a direct role in how some of China’s biggest and most successful companies do business.

This past summer, Chinese officials met with the country’s two most powerful internet tycoons, Jack Ma of Alibaba and Pony Ma of Tencent, to talk about deeper cooperation between state-owned enterprises and the tech giants. Just two years ago, their companies plowed billions of dollars into backing one state-owned telecommunications company.

In September, officials in the Chinese city of Hangzhou said they would appoint a government representative to serve as a liaison in the top offices of companies based there, including Alibaba. They said the goal was to improve coordination between government and business.

Businesspeople who don’t get on board risk becoming targets. Wang Gongquan, a billionaire venture capitalist who advocated more liberal political and social policies, was detained in September 2013 and jailed for five months. Ren Zhiqiang, a property developer, found his social media accounts deleted when he used them to criticize the party’s tightening control over discourse and is no longer allowed to leave the country. Since the protests began, Beijing has taken a more direct role in Hong Kong.

State-controlled media has castigated Cathay Pacific and other employers whose workers joined the protests. Beijing has urged representatives from nearly 100 of China’s biggest state-run companies to step up investment and assert more control of companies in Hong Kong, according to Reuters. Now the government is taking on Hong Kong’s property developers, a group that has long sought to stay in Beijing’s good graces.

Hong Kong’s largest pro-Beijing political party in September called on the city government to take back land from property developers to build affordable housing. Some property companies have said they would turn over some plots, though Mr. Li has not made his plans public. Beijing’s accusations against Mr. Li and the other real estate tycoons aren’t groundless. The cozy relationship between the Hong Kong government and wealthy property developers has long drawn criticism from experts who say it worsens housing affordability.

But Beijing’s heavy-handed ways aren’t likely to solve the problem. Mainland cities like Beijing, Shanghai and Shenzhen rank among the world’s most expensive housing markets despite state control. Those efforts also aren’t likely to satisfy the demonstrators, who are trying to defend their individual rights against Beijing’s growing sway over the city. Giving Beijing a bigger role in Hong Kong’s economy goes against the goal. Through his foundation, Mr. Li has called the accusations against him “unwarranted,” and said he hoped that all parties would seek dialogue instead of inciting conflicts. His representative didn’t respond to a request for comment.

Chinese media has been less specifically aggressive with Victor Li, one of Mr. Li’s sons, who now runs the day-to-day operations of the Li empire. Richard Li, another son with his own property and telecommunications investments, took out ads opposing Hong Kong independence after the Chinese online community accused one of his companies of supporting a pro-independence pop singer. Mr. Li’s career spans decades, and offers a glimpse at how the Communist Party’s view of business has changed over the years. He arrived in Hong Kong as a poor refugee fleeing Japanese forces during World War II.

From that modest background, Mr. Li made a fortune through real estate, ports, telecommunications and utilities, earning the nickname “Superman” from admiring Hong Kongers. Politically, Mr. Li’s instincts have long been strong. China’s state media lauded Mr. Li as a “patriot” for his philanthropic work in the mainland.

He met frequently with past Chinese leaders who were eager to show they supported the emerging class of Chinese business leaders. Deng Xiaoping, China’s paramount leader in the 1980s, held two one-on-one meetings with Mr. Li. Deng’s successor, Jiang Zemin, stayed at Mr. Li’s Harbor Grand Kowloon hotel during his three visits to the territory and had meals with him. Mr. Li has also met with Mr. Xi, when the future Chinese leader was a provincial official.

But Mr. Li in recent years has shown an independent streak just as the Communist Party began seeking greater control. His company started selling off assets in the mainland and Hong Kong in 2013 as the property market became more uncertain. State media portrayed his retreat as lack of confidence in China’s economy.

Two years later, a Chinese think tank controlled by state media published an article, headlined “Don’t Let Li Ka-shing Get Away With It,” that argued that Mr. Li should shoulder more social responsibility by helping the poor since he had made so much money in China through his political connections. Mr. Li then issued a three-page statement saying he wasn’t withdrawing from China. Mr. Li has also demonstrated some political independence.

He didn’t support the 2012 candidate whom Beijing picked for Hong Kong’s top leader. During the 2014 Umbrella Movement, a Xinhua News Agency article criticized him for not being “clear whether or not he agreed with the appeals of the protesters.”

During the latest round of protests, state media has again portrayed Mr. Li as ambivalent. It criticized the tone of newspaper ads he bought that called for peace on Hong Kong’s streets. Then in September, at a Buddhist event in Hong Kong, Mr. Li said: “We hope the young people can take the big picture into consideration.

For those at the helm, we hope they can give the masters of our future a way out.” A full-throated denunciation of the protesters it was not. For others, the public pressure on Mr. Li sends a chilling message, said Chen Tianyong, an entrepreneur who left China and settled down in Malta this year after becoming disillusioned with the way Beijing managed the economy.

“If they can turn against Li Ka-shing so easily,” Mr. Chen said, “one can imagine what could happen to the rest of us.”