A practical aspheric non-null testing method of combining numerical simulation with real interferometric testing was proposed.Numerical simulation and analysis of using three typical spherical reference wavefronts to test ideal aspheric surface were carried out by MATLAB.According to simulation results(simulated interferograms),the smallest one of wavefront aberrations between ideal aspheric surface and three typical spherical reference wavefronts,respectively,was selected as the wavefront under test for aspheric full aperture test; in this case,the theoretical interferogram of aspheric non-null testing was obtained by adding an appropriate amount of tilt and defocus amount to the wavefront under test.