An investigation is proposed to evaluate fatigue crack performances of compact tension (CT) specimen of 6061-T6 aluminum alloy treated by large area overlapped both-sides lasr shot peening (LSP) along given orbit using YLSS-D25A/M laser, operating at 20 ns with 1064 nm radiation. Residual stress distributions before and after LSP are studied, effectiveness of LSP in retarding rate of pre-cracked CT specimen as well as their fatigue fracture characteristics after LSP are also discussed. Results show that LSP can effectively decrease crack growth rate, as a consequence, fatigue life is extended by 64.4%. Macro and micro fatigue fracture morphology of fatigue cracks of CT specimen after LSP indicates that tensile stress axis is perpendicular to crack plane in expansion area while apparent fatigue striation exists on section of front view. Fatigue striation space increases with gradual growth of crack.