Ф1.3 m concave ellipsoid reflector is the primary mirror of a remote sensor optical system, and its centering accuracy is demanding. Because the reflector had large aperture and long curvature radius of the vertex, it is difficult to center by centering instrument method, and the accuracy was low. By analyzing the compensating phenomena between the two kinds of off-center of aspheric surface, it could be seen that the accuracy of contact measurement centering by laser tracker was only 0.15°. The accuracy of contact measurement centering by three-coordinate instrument measuring instrument can reach 0.005°, but its range was limited, and repeated handling in optical processing will cause inconvenience. The Offner zero compensation test was used to verify the optical path for interference centering. The interference method converts the eccentricity of the mirror into the primary aberration of the detection system wavefront, which can also achieve an accuracy of 0.005 °. The error source of this method was mainly the focus position error of interferometer, which was a systematic error. It could be eliminated by multiple centering measurements with rotating mirrors. The maximum deviation of off-center was only 0.023 mm and 0.002°, compared with the results measured by the three-coordinate instrument. The in-situ centering measurement of large aperture concave aspheric mirror was realized.