Aiming at null measurement has the flaws of narrow scale and high cost, authors present a novel measure method with large-scale and low cost to test steeper aspheric surface, namely, simulative compensator and two wave-length phase shifting interferometry. Basing on principle of two-wavelength interferometry and computer-stored compensator, we apply the simulative compensator into the two- wavelength phase shifting interferometer, and it will enlarge the measure scale. In order to decrease the high frequency, compare the standard wavefront produced by simulative compensator with interferential pattern produce by interferometer, the departure between the standard wavefront and interferential pattern is processed the least by adjusting standard wavefront. During the date sample and process, we use sub-Nyquist principle to enlarge measure scale. According to computer simulation result demonstrate that the simulative compensator and two wave-length interferometry presented by this paper can test large departure aspheric surface, the departure of aspheric surface from best fitting sphere attain to thousand wave length. The measure scales of the novel metrology is larger several hundred wavelength than conventional non-null interferometry, and overcome the trivial narrow-scale of null interferometry.