Speaking to reporters on the plane on June 24, Mr. Mattis avoided any harsh criticism of China as he had recently said.
Instead, Mattis stressed that he would focus on strategic security issues in negotiations with Chinese leaders.
A key topic of discussion this weekend was the issue of denutiarization of the Korean peninsula and the role of Beijing - a long-time ally with Pyongyang, according to officials.
"I want to go to China for dialogue. I don't want to immediately place certain expectations on what they are going to say. I want to go there and listen," SCMP quoted Mattis as saying.
Mattis's change to a diplomatic rather than diplomatic direction reflects the US administration's recognition of China's important influence over North Korea, in the context of ongoing negotiations for Pyongyang to abandon nuclear power.
A US official said that although Mr. Mattis was willing to express Washington's views on China's Militarization of the East Sea and other conflicts, the Pentagon boss did not want to start the dialogue with "stimulation". Instead, the goal of the visit is to have higher-quality negotiations on military relations between the two countries.
However, last month, Mattis unexpectedly withdrew China's invitation to participate in the RIMPAC multinational exercise in the Pacific Ocean, in response to Beijing's sending of weapons to artificial islands in the East Sea.
A few days later, Mattis publicly threatened with "greater consequences in the future" if mediatization continued.
But this time for Mr. Mattis, North Korea will be the main topic in dialogues with senior Chinese officials - according to SCMP. While Washington wants Beijing to use its influence to strengthen denuclearization talks with Pyongyang, it also wants China to maintain its commitment to implement sanctions against North Korea, as part of a pressure campaign.
This is Mattis' first trip to mainland China, both individually and as defense minister. The last time a Pentagon boss visited China was a visit by former Defense Minister Chu Hagel in February 2014.
