Abstract: Optical frequency combs (OFCs) are powerful instruments in space applications with excellent characteristics of ultra-short pulse in the time domain, wide spectrum in the frequency domain and millions of mutually coherent, perfectly spaced comb modes which provide a link from the optical frequency to the radio-frequency and consequently enable unprecedentedly precise, absolute measurements of optical frequencies. Great breakthrough progresses have been made in many application fields over years. In this paper, the technical status of OFCs’ generation scheme is summarized, and the research progresses in space application fields such as time-frequency reference, time-frequency transmission, precision measurement and high-capacity coherent optical communication are described and analyzed. In the field of time-frequency reference, the OFCs provide important support for the establishment of high-precision time and frequency standards. In the time-frequency transmission field, the OFCs help achieve precise time and frequency synchronization, providing high-precision time-frequency comparison and distribution for various systems at global, terrestrial and intercontinental scales. In the precision measurement field, the OFCs offer high-precision rapid measurement over a wide range of working frequencies, showing broad application potential in precise mapping, optical positioning, target tracking, and remote sensing. In the field of high-capacity coherent optical communication, the OFCs exhibit outstanding advantages in strong coherence of multi-carrier, enabling the realization of high-speed and stable optical communication systems to meet the demands of high-capacity data transmission. With further advancement in the generation and control techniques, the OFCs will play a more significant role in space applications. However, for practical engineering applications，it is still necessary to address challenges related to environmental adaptability, system integration, stability and reliability, etc.