Convex conic aspheric surface is widely used in the reflect optical instruments, but it is difficult for fabrication and testing at all times. Based on third-order aberration theory and the self-aplanatic capability of refractive aspheric surface, two testing methods of transmitting autocollimating testing and reflect autocollimating testing are suggested, avoiding the aperture of auxiliary lens is overmuch larger when the Hindle testing is applied. The testing precision of the two methods are analyzed by a example of ?准600R-C system. The difference between Hindle testing and autocollimating testing are also discussed. As a result, autocollimating testing of convex conic aspheric surface is useful and convenient for testing.