Since 1970’ IGGCAS has set up closed cooperation with institutions and universities of German, England, Belgium, Italy, USA, Japan and Korea. IGGCAS hosted a number of international conferences, such as 12th international Earth Tide Symposium, International Symposium of Active Geospheres Investigations, and Workshop on Crustal Movement in Eastern Asia. IGGCAS sponsored or participated a series of international cooperation projects, such as Global gravity changes and its application in geodynamics, EGNOS testing and navigation of Sino-Europe Galileo Project, GGP, APS, ILP II-4, WPLTN, DOSE,G-GRAMOPHONE. IGGCAS conducted Sino-Japan joint project Gravity Survey in Eastern Asia by superconducting gravimeter and China-Japan-Korea joint project study crustal movement in Eastern Asia by GPS technique, as well as cooperation with four universities of England and USA, for research on wetland system.

Prof. Hsu H T held president position of the international Committee of Earth Tide, and vice-president position of the International Committee of Gravity, with two successive tenure terms. He was a member of the Editorial Board of Journal of Geodesy, and Chinese committee member of IUGG. Prof. Sun is now a member of the Editorial Board of Journal of Geodesy.