Because of the current testing methods restricting the application of large-aperture, large-relative aperture concave aspheric mirrors, a large-aperture, large-relative aperture concave aspheric surface testing method based on near-double-lens is proposed. Different from the Offner testing method, the lens in the testing optical path is used as a correcting lens and a self-collimating-lens in the optical path before and after reflection. The initial structure is derived according to the third-order aberration theory. The testing results of using a single lens and a near-double-lens as correcting lens are shown in diagrams respectively and analyzed. The experimental results show that the testing method in which the self-collimating lens is located in front of the conjugate back point can be used for the testing of large-aperture, large-relative-aperture concave aspheric mirrors. The proposed method is simpler and more convenient in terms of processing, assembly and use, and provides a new idea for the testing of concave aspheric surfaces, and lays a foundation for the use of three lenses to test concave aspheric surfaces with larger apertures and relative apertures.