The so-called "investigations" under legislation, such as section 301 of the US Trade Act of 1974, risk igniting a trade war between the world's two biggest economies, Liu said in the article carried by The Guardian newspaper.
"But a trade war, which would be unpopular, damaging and anachronistic, should and can be avoided," he said.
"There would be no winner in a trade war," the Chinese ambassador said, "If the Trump administration, by announcing unilateral protectionist measures, believe there could be, it must be suffering the damaging after-effects of the years in which it had a hegemonic mindset. It must also be suffering from historical amnesia."
"Should a trade war erupt, the multilateral trade system would bear the costs, and the global economy, which is yet to fully recover from the last crisis, would be at risk again," he said, "To uphold the rules-based international trade regime as well as to safeguard its own legitimate rights and interests, China has taken counter-measures."
Raising tariffs will not balance US books because the real problem is its excessive consumption and low saving rate, Liu noted. "The trade imbalance with China is further aggravated by the long-term US restriction on high-tech exports to China."
"The Trump administration is putting domestic law above international law and forcing America's trading partners to make concessions," he said, "It is tantamount to returning the international trade order to the 'law of the jungle'. In the face of this, China had to act."
"China has not, however, closed the door to negotiations," he said. "On the contrary, we will continue to deepen reform and open up on all fronts with a view to building closer trade and economic partnerships with the world."
It is China's consistent position to address trade disputes through negotiations and consultations, he said. "China stands ready to carry out constructive negotiations with the United States on the basis of mutual respect, equality and mutual benefit, as long as the United States abandons unilateralism and trade protectionism."