In order to explore the mechanism of positive rake angle (PRA) grinding for diamond grit and to demonstrate the feasibility of PRA grinding, the finite element simulation software ABAQUS was used to establish a grinding model of Ti6Al4V titanium alloy with single diamond grit. Then, the change law of grinding force in the grinding process of single diamond grit with PRA or negative rake angle under different process parameters was studied and compared. On this basis, titanium alloy grinding experiments were carried out for the PRA diamond grit fabricated by femtosecond laser and the original negative rake angle diamond grit. The grinding force was measured by the dynamometer and compared with the simulation results. The grinding surface morphology was observed, and surface roughness was measured. Furthermore, the grinding force，grinding surface morphology and surface roughness between PRA and negative rake angle grinding were compared. The results show that，in single diamond grit grinding, the grinding force decreases with the increase of grinding speed, increases with the increase of grinding depth, and decreases gradually as the rake angle varies from negative to positive. And the trends of grinding force obtained by simulation are basically consistent with the experimental results. Compared with the traditional negative rake angle grinding, the PRA diamond grit also has good wear resistance, and the grinding surface with PRA diamond grit has the advantages of shallow grinding traces, fewer machining defects, and the surface roughness is reduced by 58%~66%, which can effectively improve the surface quality of grinding.