Abstract: ‍ ‍As a special bi/multi-static radar system， passive radar has significant advantages such as low cost， anti-stealth and strong anti-jamming capabilities. Compared with conventional radiation sources， geosynchronous earth orbit （GEO） satellite is used as the source to form the GEO-based passive radar system， which provides significant advantages such as wide coverage， short revisit period， and relatively high ground power density. This paper focuses on GEO-based passive radar system with one satellite transmitter and multiple receivers. In order to achieve high-precision fusion of multistatic target echoes， this paper proposes a ship target detection technique of GEO-based passive radar based on space-time integration. First， The Keystone transform and dechirp Fourier transform are used to remove the range and Doppler migrations， and accumulate the target echo energy of each receiver into the Doppler parameter domain. Then， according to the target aspect angle， distance， Doppler parameters and the analytical form of the multistatic configuration， the mapping relationship between the target echo domain and Doppler parameter domain of each receiver are established. The alignment and accumulation of target echo energy between multiple baselines are completed by compensating the differences in range and Doppler parameters between multistatic echoes. The detection and localization of the moving target for GEO-based passive radar are realized.