The microstructure of 2624-T39 aluminum alloy was analyzed by means of metallographic(OM),scanning electron microscope(SEM)and transmission electron microscope(TEM).The effects of different microstructure characteristics on the tensile properties and fatigue crack growth rate of 2624-T39 aluminum alloy were studied.Results showed that the grain size of the alloy was a typical fiber structure along the rolling direction,and the main second phase was the Al2CuMg phase.The grain size of the alloy had an obvious influence on the fatigue crack growth rate,and the alloy showed a lower fatigue crack growth rate due to the larger grain size.The crack initiation zone on the fracture surface of alloys with lower fatigue crack growth rate was relatively rough,the crack propa-gation zone had obvious fatigue striations,and the transient fracture zone had a large number of smaller dimples.