Xi has since offered concessions to the U.S., saying that he will ease tariffs on automobiles and introduce stricter intellectual property protections.
At the same time, China escalated a separate dispute with the U.S. over Trump's worldwide steel and aluminum tariffs to the World Trade Organisation.
In a Fox Business appearance this week, Mnuchin said that a trade war is "not a worry of mine" and that Trump merely wants "free and fair and reciprocal trade."
Mnuchin said he expected to have "very frank discussions" with the Chinese this week in Beijing.
"I'm cautiously optimistic about the meetings. I don't really want to predict what's going to happen or what's not going to happen," he said.
"These are issues that President Trump has been focused on for over the last year, and hopefully we'll make significant progress. We're going there to make progress, that's our objective."
U.S. officials will be in Beijing on Thursday and Friday.
"We're looking to have a very frank discussion on trade, on the issues of the trade imbalance," Mnuchin said Monday.
Larry Kudlow, the president's chief economic advisor, will also participate in talks.
"We are representing the interests of the United States, and we have complaints - we've made no bones about that - so we wish to resolve these complaints," Kudlow told White House reporters last week.
Kudlow said, "That is our hope, that we can make some progress. It's not going to be final, it's not going to be the end of the line. It's a long process."
U.S. Trade Representative Robert Lighthizer and Trump's senior trade adviser Peter Navarro will also be a part of the U.S. delegation, as will U.S. Ambassador to China Terry Branstad, the White House says.
Chinese Vice Premier Liu He will be representing Beijing.