It comes after US and North Korean officials are thought to have met in Vietnam to discuss the site of a second summit. His delegation was seen off by high-ranking Chinese officials and honor guard at a Beijing train station and could return to North Korea as soon as Thursday morning, Yonhap said.
Chinese Foreign Ministry spokesman Lu Kang told a regular news briefing Tuesday in Beijing that Kim's visit had no bearing on US trade talks.
The meeting was followed by a dinner hosted by Xi and his wife, Yonhap said.
In the New Year speech, Kim focused on North Korea's moribund economy, saying that improving people's lives was his top priority and tackling energy shortages was an urgent task. Neither Chinese nor North Korean state media have disclosed details of the visit.
With the talks allegedly stalled due to a difference of view in terms of the denuclearization process and what rewards North Korea should get for following through, experts say the two sides will need to come to terms on that. if the high-level talks are going to be held.
Mr Hua Po, a Beijing-based political commentator, said changes in the economic model will affect politics, "which poses new challenges to his control over the country".
In the morning, Kim visited Tong Ren Tang, located in an economic-technological development zone in Beijing, which is the largest producer of traditional Chinese medicine.
In a New Year speech, Kim warned that Pyongyang may change its approach to nuclear talks if Washington persists with sanctions.
Kim's visit to North Korea's most important economic and diplomatic ally follows reports of advanced negotiations for a second summit between Washington and Pyongyang aimed at resolving the standoff over North Korea's nuclear and missile programs.
"In order to resist the high pressure of the USA, he must communicate with Xi in advance to see what steps he can take to deal with Trump", Beijing-based independent political commentator Hua Po told the AFP news agency.
"Kim needs the support of Xi so as to ask the U.S. to make substantial steps, such as providing assistance to North Korea and normalising relations with North Korea", he said.
"Kim also made the visit as a gesture that he wouldn't beg for an early North Korea-US summit", said Cha Du-hyeogn, a visiting scholar at Seoul's Asan Institute for Policy Studies.
Discussions between the USA and North Korea over Pyongyang's nuclear arsenal have stalled since Mr Kim and Mr Trump's high-profile summit in Singapore in June where they issued a vaguely worded declaration about denuclearisation.
Kim traveled to China - his most important security and trade partner - before meetings past year with Trump and South Korean President Moon Jae-in. While there have been reports of easier inspections at the North Korean border, China has denied that it's relaxing pressure on the regime.
The visit coincides with negotiations between USA and Chinese officials in Beijing to resolve a bruising trade war between the world's two biggest economies.
The North Korean leader said in his New Year's address that he might take a "new path" in negotiations if Trump didn't ease trade, travel and investment restrictions.
Shi Yinhong, an global relations professor at Renmin University in Beijing, said Kim's trip would have no direct influence on the progress of trade talks.
"On Secretary Pompeo's visit to North Korea, we don't have any travel to announce at all", US State Department spokesperson Katina Adams said in response to Radio Free Asia's request for comment Tuesday.