The meat of the summit will not happen until Thursday, when the leaders hold bilateral talks and a formal banquet.
But the Chinese are offering Trump a pomp-filled welcome after Air Force One landed in the Chinese capital.
The president was to be greeted by Chinese Vice-President Han Zheng; Xie Feng, China's ambassador to Washington; Ma Zhaoxu, executive vice-minister of foreign affairs; as well as the US envoy to Beijing, David Perdue, according to the White House.
The welcoming ceremony is to include some 300 Chinese youths, a military honour guard and a military band.
"We're the two superpowers," Trump told reporters as he departed the White House on Tuesday after for the long flight to Beijing.
"We're the strongest nation on Earth in terms of military. China's considered second."
While Trump likes to project a sense of strength, the visit occurs at a delicate moment for his presidency as his popularity at home has been weighed down by the US and Israel's war with Iran and rising inflation as a consequence of that conflict.
The Republican president is seeking a win by signing deals with China to buy more American soybeans, beef and aircraft, saying he'll be talking with Xi about trade "more than anything else".
The Trump administration hopes to begin the process of establishing a Board of Trade with China to address differences between the countries.
The board could help prevent the trade war ignited in 2025 after Trump's tariff hikes, an action China countered through its control of rare earth minerals.
That led to a one-year truce in October.
But Trump is visiting Beijing when Iran continues to dominate his domestic agenda.
The war has led to the effective closure of the Strait of Hormuz, stranding oil and natural gas tankers and causing energy prices to spike to levels that could sabotage global economic growth.
The US president declared that Xi did not need to assist in resolving the conflict, even though Iran's Foreign Minister Abbas Araghchi held talks in Beijing on May 6.
"We have a lot of things to discuss. I wouldn't say Iran is one of them, to be honest with you, because we have Iran very much under control," Trump told reporters.
The status of Taiwan also will be a major topic as China is displeased with US plans to sell weapons to the self-governing island that the Chinese government claims as part of its own territory.
Trump told reporters Monday that he would be discussing with Xi an $US11 billion weapons package for Taiwan that the US administration authorised in December but has not yet begun fulfilling.
The arms package is the largest ever approved for Taiwan.
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