The invention provides a method for comprehensively evaluating optical performance of a semi-ellipsoidal reflecting surface. The method comprises the following steps that the overall surface shape isdetected and the reflectivity is measured; wherein the detection of the overall surface shape mainly comprises the steps of respectively placing a diffuse transmission plate and a first camera at a focal point A, B of a semi-ellipsoid; the laser after beam expansion and collimation is split by the beam splitter, the reflected light of the beam splitter is incident to the diffuse transmission plate, reaches the semi-ellipsoidal reflecting surface after scattering, and is reflected and converged to the first camera by the semi-ellipsoidal reflecting surface; a second camera is placed on the transmission light path of the beam splitter and the position of the focal point A in an aplanatic way; the second camera and the first camera respectively shoot an incident light spot and a light spot conjugate image; the incident light spot is compared with the conjugate image of the incident light spot, and the shape precision and the surface roughness is evaluated according to the distortion and the fuzzy degree of the conjugate image; and the reflectivity measurements comprise a local reflectivity measurement and a total reflectivity measurement. The method for comprehensively evaluating optical performance of the semi-ellipsoidal reflecting surface has the advantages of high detection efficiency, low implementation cost, easy operation, interference resistance, comprehensive system and the like.