The IPOE has been dedicated to international collaboration since its foundation over 20 years ago. During this time, an intense and in-depth cooperation with several well-known research institutes have been established globally, including with Germany, the United States, Russia, Canada, Japan, Singapore, France, Switzerland, Australia, and the United Kingdom, both the depth and breadth of which are being expanded. By virtue of the long-held tradition of the internal cooperation at Tongji University, the IPOE has participated in various international communications and exchanges, such as inviting well-known overseas scholars to deliver lectures, promoting academic exchanges among the researchers, retaining high-level overseas talents, co-directing the applications for international projects, and hosting international seminars and conferences. International cooperation has not only benefited multiple groups, including the university, institute, researchers, as well as the students, but also enhanced the international influence of the IPOE regarding the depth and breadth of the research work.