This paper mainly simulates the fatigue life of specimens treated by laser shock processing(LSP), and studies the effects of LSP on fatigue life. Two groups of 7050-T7451 aluminum alloy specimens pull-pull experiment are performed. One group of specimens is untreated, while another is treated. The results of experiment indicate that under the stress of 101.3 MPa, two groups of average fatigue life are 26024 and 108336 cycles respectively, raised to 416.3%. The results of numerical simulation indicate that two groups of average fatigue life are 25400 and 102870 cycles respectively, raised to 405%. The result of experiment agrees with that of numerical simulation quit well. The study shows that the residual stress is generated by LSP on the surface of specimen, thus the fatigue life increases obviously.