To enhance the security level and practicality of optical validation technique, an optical multiple-level security validation method is proposed based on the multiplexing of orthogonal polarization states in threedimensional space. Two phase-only masks are generated by adopting the designed multiple diffractive planes and multiple signal windows phase retrieval algorithm, in order to reproduce Fresnel diffraction field with all of the subblocks which are obtained by the partition of the validated image distributed in specific locations in threedimensional space. One of the two phase-only masks is taken as the system lock. The other one is acted as the security validation key. The two phase-only masks are illuminated by orthogonal polarized respectively. The control of both intensity distributions and polarization distributions in different place are achieved in three-dimensional space. Only when both the security validation key and the three-dimensional orthogonal polarization map key are obtained, the validated image is retrieved. The correlation coefficients between the verification image and simulation or experimental results are 0.93 and 0.79 respectively, which shows the proposed system is a quite compact setup, with both high security level and multiple-level validation functionality.orthogonal polarization multiplexing