His trip to China, the fourth in the past 10 months, is believed to be an effort to coordinate with his only major ally ahead of a possible second meeting with Trump.
While Trump says he considers Xi key to enticing Kim into taking concrete steps toward denuclearization, the president's own relationship with his Chinese counterpart has frayed over the U.S.
Mr Moon also said the North would have to seek a compromise in a second summit between North Korean leader Kim Jong-un and US President Donald Trump, which he said could be imminent, in order to resolve the impasse.
North Korea will "make efforts for the second summit between (North Korean) and USA leaders to achieve results that will be welcomed by the worldwide community", Kim was quoted as saying by China's official Xinhua News Agency.
Experts think Kim's China trip was meant to discuss strategies with his closest ally ahead of a possible summit with Trump, adding that it also appears aimed at strengthening the North's negotiating leverage by demonstrating its strong ties with Beijing. "China has actually been a good partner in our efforts to reduce the risk to the world from North Korea's nuclear capability; I expect they will continue to do so".
South Korea's Yonhap News Agency said Kim visited a technology development zone in China and spent around 20-30 minutes touring a factory run by famed traditional Chinese medicine maker Tong Ren Tang.
China and Russian Federation, who both wield vetoes on the United Nations Security Council, have called for easing sanctions to reward Kim's move past year to halt weapons tests and dismantle some testing facilities.
During his annual New Year's Day address last week, Kim said it was his "firm will" that North Korea will no longer produce or test nuclear weapons. "We have maintained close communication and shared information", he added.
Relations between China and North Korea had deteriorated in recent years over Pyongyang's nuclear activities, but ties appear to have warmed, with Kim meeting Xi 3 times last year to pay his respects and keep him informed about developments.
Mr Moon, who has over the past year played mediator between North Korea and the U.S., said at a news conference on Thursday that Seoul would cooperate with the USA in resolving the issue of sanctions on North Korea.
Pyongyang and Washington have been struggling to find a breakthrough despite a pledge by Mr Kim at his landmark summit with Mr Trump in Singapore in June to work towards denuclearisation.
North Korea wants relief from the multiple sets of sanctions imposed on it over its nuclear weapons and ballistic missile programmes, while the United States wants the measures to remain in place until it gives up its arms - something Pyongyang has made no public promise to do.
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North Korea is also demanding that the United States and South Korea first issue a peace declaration to formally end hostilities and replace the armistice that has been in effect since the Korean War ended in 1953.
He then went to the Beijing Hotel where he was expected to have lunch with Xi before his departure.
"For North Korea itself, 2019 is his strategic turning point".
"China will also introduce some successful experiences to Kim to help North Korea achieve economic transformation and realise the denuclearisation of the peninsula as soon as possible", Mr Lu told AFP.
"Under the utmost care of Comrade General Secretary, the DPRK-China relations previous year were elevated to a new height and a new chapter was written", Kim said.
Hua, the Beijing-based analyst, said changes in the economic model will affect politics, "which poses new challenges to his control over the country".
"For this point, he must ask for advice from China".
Chinese Foreign Ministry spokesman Lu Kang told a regular news briefing Tuesday in Beijing that Kim's visit had no bearing on USA trade talks.
Some analysts say China could use its cooperation on the North Korean issue as a bargaining chip in the U.S. trade talks.
But Hua said Kim's visit would have a "limited" effect on the trade negotiations.
"The Sino-US trade negotiations are a matter between China and the US".