This paper aims to examine the effect of shear lip formation from cross-sections an fatigue crack propagation rate in order to study the fatigue fracture behavior of the high strength aluminum material(Al 2024-T3). The following tests were achieved from this research. 1. As a result of depressing shear lip artificially by adding a side groove to a specimen, it is shown that the propagation rate of fatigue crack is faster than that of general specimen. 2. Through the two-step load test, the phenomenon that the shear lip decreases in the part of changed load gets observed. Consequently it is shown that they crack propagation rate gets faster.