The mainly ethnic Chinese city-state, which also hosted a China-Taiwan meeting in 1993 that helped lead to a thaw, is celebrating 25 years of diplomatic ties with Beijing.
Singapore's national broadcaster Channel NewsAsia showed Xi and his wife Peng Liyuan emerging from his plane at Changi Airport before full military honours and a state banquet.
Xi will first meet President Tony Tan and Prime Minister Lee Hsien Loong, after which he is scheduled to meet Ma at the Shangri-La hotel at 0700 GMT on Saturday.
"Singapore was requested by both sides to help facilitate the meeting," the Singapore foreign ministry said in a statement on Wednesday.
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"As a close and longstanding friend of both Mainland China and Taiwan, we are happy to facilitate and be the venue for their direct dialogue," the ministry said.
"Singapore has consistently upheld a 'One China' policy and supported initiatives that contribute to the peaceful development of cross-strait relations, including direct exchanges between the two sides such as the historic Wang-Koo talks held in Singapore in 1993," it added.
Singapore's then-prime minister Lee Kuan Yew acted as a channel for messages between the two sides before the talks.
Although Taiwan is a self-ruling democracy with a fierce sense of independence, China considers it part of its territory to be reunified by force if necessary.