Abstract: In this paper, a cross-section microscopy method was used to examine the shape and depth of subsurface cracks of ground wafers under nine sets of rough grinding parameters. Results show that 70% of the cracks are diagonal and chevron crack, and 30% of the cracks are median, fork and lateral cracks. Crack shapes are independent of grinding parameters. The depth of crack increases with increasing distance from the wafer center, and the crack depth in <110> crystal orientation are greater than that in <100> crystal orientation. With the increase of the wheel feed rate, the crack depth increases. With the increase of the wheel rotation speed, the crack depth decreases. With the increase of the wafer rotation speed, the cracks depth decreases first in the range of 150-200r/min, and then increases in the range of 200-250r/min. Based on the experimental results, an optimized grinding condition is proposed.