This proceedings book contains selected and expanded contributions presented at the 7th International Symposium of Space Optical Instruments and Applications, held in Beijing, China, on Oct 21–23, 2022. The meeting was organized by the Sino-Holland Space Optical Instruments Joint Laboratory and supported by Beijing Institute and Space Mechanics and Electricity. In the recent years, space optical payloads are advancing toward high spatial resolution, high temporal resolution, high radiometric resolution, and high spectral resolution and becoming more and more intelligent. Commercial remote sensing industry has made steady progress in terms of the scope of satellite systems and applications. Meanwhile, space optical remote sensing data has been extensively applied to monitoring of resources, meteorology, ocean, environment, disaster reduction, and many other fields. The symposium focused on key innovations of space-based optical instruments and applications and the newest developments in theory, technology, and applications in optics, in both China and Europe. It thus provided a platform for exchanges on the latest research and current and planned optical missions. The major topics covered in these conference proceedings are: 1) Advanced space optical remote sensing application technology. 2) Deep space exploration and astronomical observation technology. 3) Advanced space optical remote sensing instrument technology. 4) Commercial optical observation technology and services.