US Defence Secretary Donald Rumsfeld is visiting Beijing to help boost US military ties with China.
Mr Rumsfeld said the United States wanted Chinese help in curbing North Korea's nuclear programmes and fighting terrorism.
Washington also hopes to increase military-to-military exchanges, which have lagged behind economic and political relations amid mutual wariness highlighted by the collision of a US spy plane and a Chinese fighter jet in 2001.
"We'd like to see them improve and I believe that (China) would, too," Mr Rumsfeld said of bilateral military ties. "The question is if we can find ways to do it that are comfortable from both nations' standpoint."
China, with its rising regional and global clout and its fast-growing economy, is "a country that we would like to see engage the world, as they are, in a peaceful and constructive way," he told reporters.
But in a major speech in Singapore in June, Mr Rumsfeld said China, after years of double-digit military budget growth, was upsetting the balance of power in Asia, where the United States maintains key alliances with South Korea and Japan.