Spacecrafts for earth and celestial observation play a key role in important fields related to national economic and social development, such as deep space and polar exploration, military investigation, surveying and mapping of land and resources, geological and agricultural disaster monitoring, marine observation, meteorological observation and environmental monitoring. The on-orbit structure of the remote sensing spacecraft may undergo micro deformation because of extreme temperature change in space, gravity, debris impact, fatigue, etc. The on-orbit micro deformation monitoring plays an important role in ensuring the realization of functional indicators of remote sensing spacecraft and the reliability and service life of the system. Optical fiber monitoring technology is regarded as one of the most potential on-orbit monitoring technologies for remote sensing spacecraft. After research and development over the past three decades, it is evolving from laboratory research to engineering application. However, there are some problems that limit the application and development of this technology, which need to be solved urgently. Therefore, this article reviews the main technologies for monitoring the micro deformation of the structure of remote sensing spacecraft, analyzes the main technical types, technical advantages and disadvantages, micro deformation field reconstruction algorithm, on-orbit applicability, and typical application cases of optical fiber monitoring, and illustrates the key problems to be studied and solved and the future development direction.