The work aims to improve residual compressive stress and microhardness on cemented carbide to provide guidance for the study on wear resistance of cemented carbide tools in subsequent laser shot peening. Nd:YAG laser with 1064 nm long pulse wave and 15 ns wide pulse was used to impact and strengthen the surface of WC-Co cemented carbide. Digital microhardness tester and X-350 residual stress tester were respectively adopted to evaluate the distribution of hardness and residual stress on cemented carbide before and after LSP (Laser Shot Peening). The scanning electron microscope was used to analyze surface morphology and the section microstructure. At the laser energy of 5 J, the surface had lots of holes but WC grains did not change obviously. At the laser energy above 10 J, holes and depressions basically disappeared and WC grains were refined. After LSP, 10~23 mm dense layer was formed on surface and uniformly distributed on γ phase in plastic deformation area. Compared with the surface without LSP, the microhardness and the residual compressive stress increased by 34.2% and 77% respectively and the average friction coefficient decreased from 0.5033 to 0.4214 after LSP. LSP improves microstructure, residual stress state and microhardness of WC-Co cemented carbide and is beneficial to improve the wear resistance of WC-Co cemented carbide.