The traditional Mirau interference microscope based on the PZT phase shifter has problems of long sampling interval, environmental disturbance sensitivity and non-adjustable fringe contrast. To address these issues, a polarization Mirau interference microscope is proposed for transient microscopic profile testing. To meet the testing requirements for various tested objects with different reflectivity, a linear grid polarizer is employed as a polarized beam splitter in the system. In this way, the polarization splitting and adjustable fringe contrast is achieved. Four polarization phase-shifted interferograms are instantaneously obtained with a polarization camera. In which, the influence of environmental disturbance is effectively reduced. The measurement error introduced by the polarization components is modeled and analyzed, and the actual polarization aberration is obtained to eliminate the corresponding systematic error. To remove the field of view ( FOV) error in the polarization camera, the FOV error calibration method based on phase interpolation is also studied. Based on the analysis of the influence of system components on the measurement accuracy, the corresponding error calibration method is proposed. The accuracy and feasibility of the proposed polarization Mirau interference microscope are demonstrated by experiments. Experimental results show that the measurement accuracy and repeatability are better than 1 / 100λ and 0. 1 nm, respectively. The measurement system has advantages of adjustable fringe contrast, transient measurement and compact in structure, which provides a feasible method for online testing of micro profiles and micro structures of various components.