The Noise-immune algorithm is applied to unwrap the InSAR data.The characteristic of the Noise-immune algorithm is analyzed.In order to get a better result in the unwrapping of the InSAR data using the Noiseimmune algorithm

a refinement is presented.Based on the two-point criterion

the three-point criterion is presented.In order to improve the stability of phase unwrapping

we present a hybrid algorithm which is formed by combining the two-point criterion and three-point criterion.When unwrapping the interferogram of bad quality

the two-point method may be not convergent

the hybrid algorithm can solve this problem.The hybrid algorithm can improve the stability of phase unwrapping without losing the accuracy.The computer simulation result of the simulated data and true InSAR data proves the validity of our algorithm.