In order to investigate the effect of laser shot peening (LSP) on fatigue crack propagation of 6061-T6 aluminum alloy under different stress ratios, finite element software ABAQUS and fatigue analysis software MSC.Fatigue are used to establish the prediction model to analyze the effects of different stress ratios (R=0.1, 0.3, 0.5) on crack propagation induced by LSP. The effects of residual compressive stress on the crack closure under different stress ratios are studied and the increase of fatigue life is predicted. The results show that fatigue crack growth rate decreases after LSP, compared with the untreated sample under three stress ratios. The value of stress ratio significantly affects the fatigue life of compact tension (CT) specimen after laser shot peening, however, the lower value of stress ratio is, the more the increase in fatigue life attained by LSP is.