Abstract: Distributed satellites Interferometric Synthetic Aperture Radar (InSAR) can provide large baseline, by which the sensitivity to topography measure can be improved. But large baseline arises the difficulty in phase unwrapping procedures. Combined the characteristic of multibaseline of distributed satellites InSAR system, a method that utilizes the multibaseline data fusion is proposed to solve the problem of phase unwrapping brought by large baseline in this paper. Maximum likelihood (ML) method that is an effective two-baseline data fusion algorithm is adopted to estimate interferometric phase of distributed satellites InSAR system. The simulation results show that the phase unwrapping accuracy via multibaseline data fusion is higher than that of direct phase unwrapping of large baseline interferometric phase.