1. January 1980: Harold Brown

Brown visited China, the first US secretary of defense to visit China since 1949.

2. September 1983, October 1986: Caspar W. Weinberger

Weinberger is the first US secretary of defense to visit China twice.

3. November 1988: Frank Carlucci

During his China tour, Carlucci asked the Chinese side not to sell missiles to Middle Eastern countries.

4. October 1994: William Perry

As the first defense secretary to visit China after 1989, Perry sought to rebuild military ties, which had been suspended for five years.

5. January 1998, July 2000: William Cohen

"Throughout good times and bad, we always maintain the ability to have constructive dialogue and to be able to sit across from one another to discuss issues openly, frankly, honestly and in a very positive and constructive dialogue," Cohen said while visiting the Ministry of National Defense of China in 1998.

Cohen's visit in 2000 was his first since China-US bilateral ties were severed following the 1999 bombing of the Chinese embassy in Belgrade, Yugoslavia, during a NATO joint operation.

6. October 2005: Donald Rumsfeld

"Over the years, of course, the US-China relationship has encountered some challenges, to be sure, but challenges also offer opportunities - opportunities to learn from each other," Rumsfeld said during a visit to China. After the midair collision by Chinese and American aircraft in April 2001, the US Department of Defense announced a unilateral suspension of all military exchanges between two countries. This was ended by Rumsfeld's China trip, and he became the first senior US official to visit the headquarters of the Second Artillery Corps of China.

7. November 2007, January 2011: Robert M. Gates

In his first visit to China, Gates called for greater transparency from the Chinese side on its strategic military motivations, decision-making, and key capabilities to avoid "misunderstanding and miscalculation".

"Our exercises have not been directed in any way at China. Rather they have been the result of our growing concern over the provocative behavior of North Korea," Gates said.

During his second visit, Gates shared with Chinese officials US concern about the Democratic People's Republic of Korea, and the need for stability on the peninsula.

8. September 2012: Leon Panetta

"Our rebalance to the Asia-Pacific region is not an attempt to contain China. It is an attempt to engage China and expand its role in the Pacific. It's about creating a new model in the relationship of our two Pacific powers," Panetta said in a speech at the People's Liberation Army's Armored Forces Engineering Academy. During his China trip, Panetta devoted himself to explaining the policy of "rebalancing" to both Chinese leaders and military officials. As Japan unilaterally "nationalized" China's Diaoyu Islands days before this visit, mediating territorial disputes was also a major mission.