The sparse coherent target points and speckle noise hinder the application of InSAR technology in deformation monitoring. In order to solve this problem, this paper proposes a new polarimetric phase optimization method (EVD-FPO) based on eigenvalue decomposition and adaptive filtering. This method uses Sentinel-1A dual-polarization data amplitude information to identify DS and PS targets, and based on the temporal and spatial coherence matrix, uses eigenvalue decomposition polarimetric phase optimization technology and adaptive mean filtering technology to improve the phase quality. In order to prove the feasibility and effectiveness of this method, 17 Sentinel-1A dual-polarization (VV-VH) SAR data are used to evaluate the performance of this method. The results show that the EVD-FPO method can effectively increase the density of coherent target points and improve the phase quality. Compared with the single polarimetric amplitude dispersion method (VV- ) and the amplitude dispersion polarimetric phase optimization method (ESM- ), this method increases the coherence point target by 9.06 times and 1.64 times, respectively. Compared with the single-polarization CAESAR method, the PSs extracted is more complete. The EVD-FPO method can suppress the phase noise of the DSs while protecting the phase of the PSs, and the phase quality is better than the ESM- method and the CAESAR method.