Abstract: This paper discusses the effects on image quality of multi-channel spaceborne synthetic aperture radar (SAR) caused by time synchronization error.First,a synchronization model is built combined with spaceborne multi-channel SAR system,and the influence mode of time synchronization on SAR image is also illuminated. Then,the amplitude and position of paired-echoes in azimuth are analyzed by mathematic derivation,and the periodic effects on azimuthal main lobe are illuminated as well.Moreover,the performance deterioration of main lobe in range are presented resulted from time synchronization error.and effects on image quality caused by time jitter is researched.Finally,the simulation results justify the validity of the analysis.