Abstract: Polycrystalline diamond composite sheet is widely used as cutting tool material because of its ultra-high hardness, wear resistance and good thermal stability. When using PCD composite sheets to make tools, laser polishing can obtain better processing characteristics than traditional processing techniques. In order to explore the characteristics of the laser polishing process of the PCD composite sheet and obtain the best surface roughness, the line roughness of the femtosecond polished area was used to systematically study the influence of the level changes of the laser power, scanning speed, and scanning distance on the roughness and polishing efficiency. The law of influence. The orthogonal test method is used to optimize the combination of the three factor levels, and the mechanism of the femtosecond laser polishing PCD is initially explored. The results show that the main factor that affects the roughness is the scanning speed. Selecting the process parameters of 7 MW laser power, 1 000 μm/s scanning speed, and 12 μm scanning distance can obtain an excellent PCD composite sheet with a roughness of 33.95 nm.