The "Agreement of Cooperation between the State Science and Technology Commission (Predecessor to the Ministry of Science and Technology) of People's Republic of China and the Department of Energy (DOE) of the United States of America in the Field of High Energy Physics" was signed on January 31, 1979. Since the signature, this agreement has been renewed for 5 times, and 28 PRC/U.S. Joint Committee meetings have been held so far. Collaborative efforts have been concentrated on such major projects as: the 50 GeV Proton Synchrotron in late 1970s', the BEPC in 1980s' and the physics run in 1990s', the BEPCⅡ and the Daya Bay Reactor Neutrino Experiment since the new century.

　　IHEP has a long cooperative history with the European high energy physics community. In 1977, just after the open and reform policy was executed, the then CERN Director General, Dr. Sir. John Adams visited IHEP and met with Mr. Deng Xiaoping. In 1978, IHEP sent to DESY the first group of experimentalists since the end of the Cultural  Revolution in China. In 1981, IHEP and CERN signed the first Memorandum of Cooperation, which was later renewed several times by CAS and CERN. Since the beginning of the new century,  we have such important collaborations with our European friends as the LHC, the EXFEL, the FCPPL and the Yangbajing Cosmic Ray research, to name just a few.

　　Friendly cooperative relations have long existed among Asian high energy physics communities. IHEP and KEK have had very fruitful cooperation over the past decades.