In order to investigate the effect of two-sided laser shot peening (LSP) on fatigue crack growth of 6061-T6 Aluminum alloy compact tension (CT) specimens under different coverage areas, finite element software Abaqus and MSC.Fatigue are used to establish the prediction model. Three different LSP coverage areas, i.e. 15 mm×15 mm, 34.5 mm×15 mm and 15 mm×60 mm are selected. The effects of compressive residual stress on the crack closure by different LSP coverage areas are studied, and the fatigue life increment is predicted. The simulation results indicate that the fatigue crack growth rates of laser peened CT specimens is decreased in comparation with the untreated ones. LSP coverage areas significantly affect the fatigue life of CT specimens, moreover, the specimens treated with 15 mm×60 mm LSP coverage area gain the most obvious fatigue life improvement.