The problem of direction of arrival (DOA) estimation based on a polarization sensitive array (PSA) is considered in this paper. In the environment of the mixture signal, a novel DOA estimation for both the independent signals and the coherent signals is proposed. The process of estimation is divided into two steps. First, the root-multiple signal classification algorithm is employed to estimate the DOAs of the independent signals. Then, the data covariance matrix which only contains the information of the coherent signals is estimated with improved vector reconstruction technique. Theoretical analysis and simulation results show that the proposed method can expand the array aperture and has small computation load as well as excellent estimation performance.