The regional coverage and precision of SAR image is growing rapidly with the rapid development of SAR imaging technique, which challenges the realtime processing of SAR image mosaic. This paper deeply analyses the characteristics of the SAR image sequence and presentes a model of complete binary tree based on segmentation for the SAR image parallel mosaic, and implements what this paper proposes by using the MPI pointtopoint communication mode under cluster in different size. Contrast experiments prove that compared with the traditional one, this method this paper presents is more effective in reducing the time of mosaic with better effect on the complete image after parallel mosaic.