In recent years, space optical payloads have advanced toward higher spatial, temporal, radiometric, and spectral resolution, while becoming increasingly intelligent. The commercial remote sensing industry has made steady progress in expanding satellite systems and applications. Meanwhile, space optical remote sensing data has been widely applied to resource monitoring, meteorology, oceanography, environmental studies, disaster reduction, and many other fields.

This proceedings volume contains selected and expanded contributions presented at the *2025 International Symposium on Space Optical Instruments and Applications*, held in Dunhuang, China, on August 15–17, 2025. The symposium was organized by the Sino‑Holland Space Optical Instruments Joint Laboratory and supported by the Beijing Institute of Space Mechanics and Electricity.

The symposium focused on key innovations in space‑based optical instruments and applications, highlighting the latest developments in theory, technology, and practice in both China and Europe. It provided a platform for academic exchange on current research and planned optical missions.

The major topics covered in these proceedings include:

1. Advanced optical technologies and new remote sensing techniques for space applications

2. Optical material technologies and photoelectric conversion devices for space applications

3. Space optics instruments and applications for deep space exploration and astronomical observation

4. Space optics instruments and applications for ecological and environmental monitoring

5. Commercial space optical remote sensing technologies and services

6. Contributions of space remote sensing to the high‑quality development of the Belt and Road Initiative

7. Integration of space remote sensing with artificial intelligence

H. Paul Urbach graduated in 1981 at the University of Groningen, the Netherlands, and completed in 1986 a Ph.D. thesis at the same university on the optimization of hydrodynamic propulsion. In 1986, he joined Philips Research Laboratory in Eindhoven, the Netherlands. During 1980, he spend four months in Signetics Research Laboratory in Sunnyvale, California, the USA, where he worked on optical lithography. In 1994, he became Principal Scientist at Philips Research Laboratory. In 2000, he became Part-Time Professor in diffraction optics at Delft University of Technology (TUDelft), the Netherlands. Since January 2008, he is Full Professor and Head of the Optics Research Group of TUDelft. He has been President of the European Optical Society 2012-2014 and 2017-2018, Member of the Advisory Board of the Dutch Minister of Economic Affairs on metrology, and Scientific Director of the Dutch Optics Centre.

Huilin Jiang graduated from Changchun Institute of Optics and Mechanics (CIOM), Chinese Academy of Sciences, China, in 1969 with a bachelor's degree and received his Ph.D. from the same institute in 1987. He is Academician of Chinese Academy of Engineering. He formerly served as President of Changchun University of Science and Technology and currently is Director of the university's academic committee. He also serves as Vice Chairman of Chinese Academy of Ordnance Engineering, Executive Director of Chinese Optical Society and Chinese Optical Engineering Society, and Deputy Director of the academic committee of the State Key Laboratory of Applied Optics at CIOM.