Ahead of his meeting with the vice premier, Trump tweeted, "China's top trade negotiators are in the U.S. meeting with our representatives".
The meetings are "going well", Trump said on Twitter.
Lovely said the presence of China's vice premier at the bargaining table, and the anticipated meeting between Liu and Trump, are encouraging.
"All of the many problems are being discussed and will be hopefully resolved", he said.
The United States and China launch a critical round of trade talks on Wednesday amid deep differences over USA demands for structural economic reforms from Beijing that will make it hard to reach a deal before a March 2 U.S. tariff hike.
President Xi said China has given a lot of attention to the Beijing Winter Olympics, and all preparations are in order and are being undertaken.
Moreover, a new complication injected itself into US-China relations on the eve of the talks when the Justice Department brought criminal charges Monday against the Chinese tech giant Huawei, accusing it of stealing technology secrets and violating sanctions against Iran.
"We hear rumblings or rumors there are some offers (by the Chinese delegation to Washington) around IP (intellectual property) enforcement, around the other sensitive issues".
Meanwhile, Mr Trump, a self-described "Tariff Man", rejected a previous proposal from Beijing to resolve the dispute with increased purchases of United States goods.
New Zealand v India 3rd ODI
Brief scores: New Zealand 243 in 49 overs ( Ross Taylor 93, Tom Latham 51; Mohammed Shami 3-41, Hardik Pandya 2-45) vs India . Skipper Virat Kohli will be rested for the final two ODIs and the subsequent T20I series against the hosts.
The talks have taken place against the backdrop of Chinese telecom Huawei's prosecution by Washington, which has sparked outrage in China and threatened the negotiation process.
"China posts slowest economic numbers since 1990 due to United States trade tensions and new policies", Trump said Jan 21.
But compelling China to reform its trade policies and treatment of foreign companies will be hard. They're coming to the White House for a meeting with Trump on Thursday afternoon.
"For the trade talks this week, nothing significant is going to happen", Okun, a trade expert and a board member of the American Chamber of Commerce in Singapore, told CNBC's "Capital Connection" on Thursday.
Chinese officials are in Washington, D.C., this week for negotiations with top US officials as the world's top two economies seek and end their trade dispute.
The US imposed tariffs on $250bn worth of Chinese goods past year.
Chinese officials deny that their policies coerce technology transfers.
Prior to being named US Trade Representative in May 2017, Lighthizer was a specialist in worldwide trade law for more than 30 years and is a veteran of trade negotiations with Japan in the 1980s.
But the impact of Trump's trade policy is also being felt by the US.
According to a person familiar with the meeting agenda, Lighthizer and Treasury Secretary Steven Mnuchin were scheduled to give opening remarks at the talks Wednesday morning. Instead, the pressure would be on the U.S.to reduce tariffs.