Aiming at the problem of removal function correction ability in removal theory of Computer Controlled Optical Surfacing(CCOS), based on the equivalent removal integral method, the correction ability of Gaussian type, triangle type, trapezoid type, pulse random compound type and other removal functions is studied. The correlation curve between the modulation parameters and the correction ability of the removal function is obtained by analyzing the error correction ability of the removal function in frequency domain. An evaluation model of cutoff correction ability of removal function based on equivalent removal integral method is established, which provides a theoretical basis for the adjustment of removal function error correction and the evaluation of removal function correction ability, so as to improve the surface quality of ultra-smooth optical elements in ultra-high precision machining of large aperture optical elements.