Abstract: The mid-spatial-frequency error (MSFR) of large aperture aspherical optical elements have a direct influence on the precision of the beam diffusion function and the energy scattering of the high energy laser. To solve this problem, we put forward a kind of multi-tool NC polishing technology of computer controlled optical surfacing(CCOS) for effective suppression of MSFR. The polishing process of semi-rigid polishing tool is analyzed by finite element methods, and the polishing process is theoretically simulated based on Bridging model. The experimental results show that the MSFR of large aperture aspherical optical elements can be effectively reduced by multi-tool polishing technology. The wavefront PSD1 value of specific spatial frequency has been restrained effectively. For the two finished ϕ460 mm elements, the wavefront PSD1 value has a 70% descend down to 2.835 nm. Besides, the PV value is less than 0.16λ(632.8 nm) and the RMS value is less than 0.02λ.