"This is the moment for stronger cooperation," the Chinese president was quoted by the official Xinhua News Agency as saying.
British Prime Minister David Cameron led a six-member delegation to Beijing, arriving Monday in the Chinese capital. Cameron's office said the agenda would focus on building a long-term relationship based on mutual respect.
Xi said both parties have a shared interest in international affairs as permanent members of the U.N. Security Council.
"We expect the U.K. to be more active and open in its collaboration with China and to create a more accommodating environment," the Chinese president said without elaboration.
Xinhua reported Chinese Premier Li Keqiang met with Cameron to discuss bilateral cooperation in the aerospace and nuclear energy sectors.
Cameron was quoted by The Guardian newspaper in London as saying his government considered engagement with China a win-win situation.
"There is no country more ready to forge a dialogue of mutual respect and understanding that can address issues of concern and advance our shared interests in the world," he said.