Based on the equations of motion and rheological theory of abrasive flow in the slit, effect between wall slip and grinding has been analyzed and grinding flow model of abrasive flow has been built in this paper. Wall pressure, wall shear stress, wall slip and the grinding force equation of abrasive flow were derived using the model. What is important, the effects of relevant factors were analyzed. The results show that wall slip is one of the necessary conditions that in abrasive flow machining, and show that main factors influencing wall slip are viscosity coefficient , grinding coefficient of abrasive flow, and the first normal stress difference. In the meantime, the results also show that grinding force in slit wall is proportional to the entrance pressure of slit. That is to say that the grinding force of per unit length in flow direction increasing dramatically with decreasing slit height.