The key technology in precession bonnet polishing was investigated to get the high-precision optical surface. First, the facility and principium of bonnet polishing was introduced and the removal function of bonnet polishing was acquired from the analysis of Preston equation and the orthogonal processing experiments. Then a new algorithm based on matrix iteration to solve the dwell time was proposed and the dwell time function was analyzed to make it convenient to the polishing. The simulation of the variance of the residual error was made through MATLAB to prove the algorithm. And the simulation result showed that the residual error can reach up to 0.1μm. Finally, the polishing experiments of plane and sphere were made to validate the accuracy of the dwell time algorithm and the practicability and precision of the precession bonnet polishing. After polishing the sphere surface PV value reached to 0.17μm. Through this the rationality of the dwell time algorithm was proved and it can satisfy the requirement of optical precision machining very well. And this also provided theoretic foundation for the later polishing for free-form surface.