Abstract: Basic theory of polarimetric synthetic aperture radar (SAR) interferometry is expatiated and the PolInSAR vegetation scattering model and Cloude three-stage vegetation height inversion algorithm are analyzed. The calculation of the three-stage algorithm is complex as it adopts initial value iterative. The paper introduces a method to combine the vegetation height estimation by the coherence coefficient amplitude and phase. This method not only keeps the precision of vegetation height estimation but also reduces the calculation of the algorithm greatly. Finally, the polarimetric SAR interferometry simulated data are used to validated the proposed method.