The center crack plate of aluminum alloy 2024-T3 is studied in this paper. Using structural detail fatigue rating method to analyze the fatigue life of different crack length and size of stop hole, the experiment fatigue life which the half crack length is 10mm/15mm/20mm and the crack stop hole radius is 2.5mm/3.5mm is obtained to verified the model. The fatigue life analysis in this method has the optimum solution When the crack length/width (2a/W) from 0.2 to 0.6, the stop hole diameter/ width (D/W) from 0.03 to 0.2. The mathematical relationship of D/W and 2a/W is find to provide reference in engineering practice.