With the development of modern optical technology, there has been a basic requirement to control the surface error in all spatial frequency ranges for precision optics. The low spatial frequency range error of the surface can be easily and effectively eliminated by CCOS methods, but for the surface error in the middle and high spatial frequency ranges, there are few effective methods to correct them. Hence it has becomes a universal concern in modern optical manufacturing because of its serious influence on some modern precision optical systems. As is proved previously, the correcting ability of middle and high frequency error can be improved by reducing the size of the polishing lap. Based on this theroy, the small ion beam figuring methode has been intruduced to solve the problem of mid and high frequency error correcting. Firstly, we studied how to gain small and steady ion beams by two methods. Then we designed a series of actual figuring experiment and computer simulation to test the effectivness of those mothods on small scale optic surfaces. The desired results have been gained to reduce the surface error from 0.111λ rms to 0.015λ rms (λ=632.8nm).