It is the first branch opened by a foreign bank in the city and UOB's seventh in the Greater Bay Area, which includes Shenzhen and Hong Kong.
UOB said the new branch will provide businesses with domestic and cross-border financial services, including foreign exchange hedging, term loans and project and supply chain financing.
Mr Peter Foo, president and chief executive of UOB (China), said: "The UOB Zhongshan branch affirms our long-term commitment to China and reflects our confidence in China's Greater Bay Area development plan."
The branch is connected to UOB's regional network to help customers expand into Asean, he added.
Zhongshan is a key transport hub and an important link connecting countries in the Belt and Road Initiative(BRI), the bank said, noting that the city has recorded strong trade and investment flows with BRI countries.
The city's outbound investment to BRI countries reached US$430 million (S$592 million) last year.
Its top trade partners are Singapore as well as Malaysia, Thailand and Vietnam - countries where UOB has an extensive presence, the bank noted.
UOB said it has been boosting support for clients as they grow within and outside the Greater Bay Area.
In October last year, its Shenzhen branch, UOB (China)'s flagship in the Greater Bay Area, moved to larger premises to accommodate additions to its team.
Earlier this year, it opened a commercial banking centre in Causeway Bay, Hong Kong's central
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