Abstract: The effects of uncoated diamond, Ti-coated and Ni-coated diamond with different bond strength on the protrusion height of diamond tool was studied through L₉(3⁴) orthogonal experiments. The SEM 3D reconstruction method was used to measure the protrusion height of diamond particles. The protrusion height of different diamonds particles were compared and analyzed. The results show that the protrusion height of diamond particles can be measured conveniently and quickly by using SEM 3D reconstruction method, the protrusion height is 221.26~321.68 μm; and the coating on the diamond surface and bond strength of diamond bits have both apparent effect on the protrusion height of diamonds particles. Moreover, the protrusion height of Ti-coated diamond is higher than that of Ni-coated diamond, and both of them are larger than that of uncoated diamond.