The material removal rate of HEP (hydrodynamic effect polishing) was mainly affected by the distribution of hydrodynamic pressure and shear stress on the workpiece surface, and the key process parameters were sought out accordingly. Based on the fluid dynamic simulation and experiment exploration, it investigated in detail how the material removal rate was affected by the wheel immersed depth, the wheel rotated speed and the polishing clearance. The analysis results show that the wheel immersed depth has little effect on the removal rate while the removal rate decreases along with the reduction of the speed and the increase of the polishing clearance. Considering the practical process condition, the optimal wheel immersed depth, speed and polishing clearance are （2/3）R, 300 r/min and 25 μm respectively. Meanwhile, the temperature stability of the polishing head was monitored, and it reached thermal equilibrium within 4 hours at start of the device. Therefore the stability of polishing clearance affected by the temperature can be guaranteed by idling with preheating section.