Abstract: A single-grit micro-cutting model is established and the burr formation process during abrasive reaming is analyzed. Side burr sectional area is taken as the evaluation index of burr size. The influences of cutting depth, cutting width and cutting edge inclination angle on burr formation are studied. The accuracy of the model is verified by experiments. The results show that plastic deformation is the important factor affecting burr formation. With larger plastic deformation, the burr sectional area is larger. Side burr sectional area increases with the raise of cutting depth and cutting width. With the change of cutting edge inclination angle from negative to positive, the amount of plastic deformation increases and the direction of material flow changes, and then the burr size grows.