The fact that the two leaders "can sit together and have equal talks has important and positive meaning, and is creating a new history," Chinese Foreign Minister Wang Yi told reporters.
"The crux of the peninsula nuclear issue is a security issue. The most important, difficult part of this security issue is for the United States and North Korea to sit down to find a way to resolution via equal talks," Wang said.
"Resolving the nuclear issue, on the one hand of course is denuclearisation, full denuclearisation. At the same time, there needs to be a peace mechanism for the peninsula, to resolve North Korea's reasonable security concerns."
Beijing is Pyongyang's sole major ally and main trading partner, but it has backed a slew of United Nations sanctions to punish the North over its nuclear and missile tests.
Despite tensions, the Cold War-era allies have sought to mend ties recently, and Kim borrowed an Air China plane to travel to the landmark summit in Singapore.