Abstract: In order to asure high machining precision and improve polishing efficiency, a new removal function of annular polishing pad based on translation-rotation motion was investigated and deduced, which was needed in disc hydrodynamic polishing. Based on translation-rotation motion, compared with the round polishing pad which is the most widely used, the highest tending factor of annular polishing pad improves by 10.25% and its form of removal function is more closer to the impulse function form. Therefore, it can reduce the convolution effect and smooth out mid-to-high spatial frequency errors. Setting the initial surface error, the pulse iteration method was used to compute the residual error and the dwell time with the same parameters. After 50 times iteration, the simulation result proves that the residual error of annular polishing pad reduces by 3.65% than round polishing pad. The polishing removal efficiency can be improved.