This paper presents a large field phase-shifting interference microscope for micro-surface topography measurement. A PZT is used as the Z-directional phase shifter. The interference microscope is the combination of the infinity tube microscope with the Mirau two-beam interferometer. Two-dimensional precision motorized stage is aligned as the scanning system in the X- and Y-direction to extend the test surface measurement range to 12.5 mm × 12.5 mm. The minimum displacement is 0.039 m and the overlapped proportion is 0.22. A fast stitching algorithm is proposed based on grid matching. According to the reflectivity of the core and the ferrule, the plate with the transmission/reflectivity ratio of 70/30 is selected to balance the interference intensity. The instrument is proved to be valid by actual measurement of the end surface of an optical fiber connector. This work has been supported by the National Natural Science Foundation of China (No.60577013) and New Teachers Doctoral Fund of Ministry of Education of China (200800561022)