Convex aspheric mirror surface is a major problem in optical inspection. A method for testing a convex aspheric mirror is proposed by using concavity autocollomatic transflective lens. The transflective lens is composed of a convex spherical surfaces and a concave one. The concave surface is autocollomatic semi-reverse half surface. With the autocollomatic semi-reverse half surface design, the wavefront can be compensated and reflected by the aspheric surface. The light can return along the original path to achieve compensation inspection. The method has the advantages of simple structure, strong detection capability and no center obstruction. Based on the third-order aberration theory, calculation formula of the initial structure of inspection system is deduced, and the key parameters of different convex aspheric mirror inspection systems are obtained. The detection optical path of a convex reflection aspherical surface r03=2000 mm, e2=－2.4 is designed, and the initial structure parameters are optimized using Zemax software. Wavefront aberration of system is less than 0.05λ. The design and simulation results show that the proposed method for testing concavity autocollomatic transflective lens is very beneficial to the inspection of all kinds of convex aspherical mirrors.