The 00Cr12 alloy heat-resistant steel was strengthened by laser shock processing (LSP) with appropriate parameters,and its fatigue limitation was measured rapidly. The effects of residual stress and microstructure change of the surface layer of 00Cr12 alloy on its fatigue life were discussed and analyzed before and after LSP. The results showed that elastic-plastic deformation was induced by laser impulse on the material surface,which resulted in residual compressive stress and dislocations of high density in the material surface,so the fatigue life of 00Cr12 alloy was effectively improved by LSP. After LSP,the fatigue life of 00Cr12 alloy was 1.6 times as much as the sample without LSP. Compared with the traditional rising and falling methods,the relative error of the results obtained by Locati multistep method was small. This method could provide reliable data for fatigue design of machines.