Mr. Trump has repeatedly made clear that he expects China, the North’s main supplier of food and fuel, to increase pressure beyond what it has been willing to do so far to force an end to the weapons programs. In an interview in The Financial Times on Monday, he was even more demanding, warning that the United States would take unilateral action to eliminate the nuclear threat if Beijing fails to act, presumably by curbing trade and assistance.

Analysts say China may be willing to increase pressure somewhat on North Korea, but well short of causing the regime in Pyongyang to collapse. Most experts believe that the North will not abandon its nuclear program unless the leadership at the top changes. China opposes this because it fears a surge of refugees into its territory and wants to keep North Korea as a buffer against a potentially unified Korean Peninsula dominated by the American military.

The United States and China may have a long-shot chance at an achievable solution if they agree to increase sanctions on North Korea and pursue more modest goals — halting North Korean missile tests and curbing the production of additional nuclear weapons — but there has been no serious sign of interest from the Trump administration.

Trade is another area where agreement is likely to be difficult, especially since these issues are still being fiercely debated inside the administration. During the campaign, Mr. Trump talked tough on China, promising to impose heavy tariffs on imports. But he has not followed through, and recently told The Financial Times that he hoped to reach some kind of deal with Mr. Xi. Administration officials said they hoped the summit meeting might produce concrete results, though that may be a lot to ask of the first encounter.

The risk in this meeting is that Mr. Trump knows little about diplomacy with China and does not have a team of China experts in place. He has already had to correct one major error; after calling into question America’s longstanding one-China policy, he retreated and told Mr. Xi in February that he would respect Beijing as the sole government of China and not recognize Taiwan.