Combined with the grinding principle, it is put forward that friction coefficient changes with the change of grinding parameter; and the grinding force model of single abrasive grain is developed based on friction coefficients of different grinding conditions. Following the theory of variable friction coefficient, the grinding force model of single abrasive grain is theoretically and experimentally researched. The research indicates that this model fully reflects the effects of grinding parameter, abrasive grains' distribution, material properties, variable friction coefficient, and etc. on grinding force of single abrasive grain, which ensure an accurately simulation of actual grinding situation. By using this model, it is predicted that grinding force of single abrasive grain in normal direction has an accuracy of about 18~36.84%; however when taking the variable friction coefficient into consideration, prediction of tangential grinding force of single abrasive grain has an accuracy of about 10~20% by using this model. Experiment proves that this study offered a new grinding force model of single abrasive grain with variable friction coefficient, which has a practical value.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.