Abstract: A new phase estimate algorithm for multi-baseline interferometry is proposed in this paper. This method consists of two steps: firstly, selects the appropriate set of baselines and unwraps the interferogram associated with the shortest baseline; then gains the unwrapped phase of the longest baseline by using the maximum likelihood estimator to extract the frequency of any complex pixel. The method proposed in this paper is simple and effective, and error propagation effect of this technique is very small. The method does not require plenty of iterative operation, even the step of phase unwrapping will be omitted when the shortest baseline is short enough. Simulation data processing results validate the effectiveness of proposed method.