Abstract: The estimation of the 2D-direction of departure（2D-DOD）and 2D-direction of arrival（2D-DOA）for MIMO radar system is investigated. A novel algorithm is proposed to unwrap the cyclically ambiguous of the angles estimated by conventional algorithm when aperture extended.The key step is to estimate the poynting vector of signal from the polarization information matrix，which is obtained by CANDECOMP/PARAFAC decomposition.In order to improve the accuracy of DOD，a stricter orthogonal constraint is proposed that the signals of spatial separated elements should be suit to the orthogonal constraint.Furthermore，every antenna in a same geometry center transmits narrow orthogonal signals simultaneously.Thus，the unambiguous estimation of DOD could be obtained from the polarization information matrix.The proposed algorithm offers a better performance through aperture extension without angle ambiguous.It requires neither peak searching nor pairing processes，and simulation results are presented to verify the effectiveness of the proposed algorithm.