As the surface shape of a reflection mirror is different from the target shape at the end stage of the grinding process, and the profilometers and common interferometers can not measure the surface error exactly, this paper proposed a method to measure the large aperture aspheric surface by using a Shack-Hartmann Wavefront Sensor (SHWS) with a large dynamic range and high precision. The principle of the measuring system for SHWS was researched, its measuring errors were analyzed and a corresponding data processing software was compiled. Using a simulation reference file, a hyperboloid reflection mirror with a diameter of 350 mm was tested by the SHWS. Results indicate that the PV and RMS of the surface error are 0.388λ and 0.043λ, respectively (λ=632.8 nm). In order to testify the measurement result, the mirror is also measured by an interferometer with a null compensator. Comparing the two testing results, the PV and RMS of the deviation are 0014λ and 0001λ, respectively, which proves the feasibility of measuring large aperture aspheric surfaces by SHWSs.