Taking W6Mo5Cr4V2 (M2) high speed steel cutter material as sample, the effect of laser shock on fatigue performance of M2 material is studied. Experiments of laser shock processing, metallographic observation, residual stress measurement and fatigue performance test on M2 samples are conducted. The mechanism of laser shock on surface microstructure, residual stress and fatigue performance is analyzed. The results show that after laser shock, the surface microstructure grains of M2 samples are refined and the grain boundaries increase, forming lattice imperfection such as dislocation and twin crystal. A certain depth of residual compressive stress layer is caused within shocked area. The residual compressive stress on cross section is decreased from surface to center. The surface residual compressive stress is maximum. In a certain distance from surface, the residual compressive stress is stable. Before and after laser shock, the average fatigue life of sample is significantly improved. Different laser shock process parameters have differert effects on the fatigue performance of the sample. By laser shock, the surface material of the M2 high speed steel is strengthened and its fatigue performance is improved.