The mechanical properties of certain aircraft’s welding simulated samples are analyzed in this article. The welding simulated sample is once-welding plate of 30CrMnSiA high strength steel. There are two productive states which are heat treatment after welding and none heat treatment after welding, respectively. The influence of heat treatment on the mechanical performance of the 30CrMnSiA high strength steel were studied by tensile test, fatigue test and morphology analysis of fatigue fracture, respectively. The results show that the welded joints’ properties maybe improved by heat treatment after welding. And the welded joints’ tensile strength and median fatigue strength increase obviously by heat treatment. By the microstructure observation of fracture, it’s can be found that heat treatment can decrease the porosity defects in welding seam and improve the fatigue performance of the welded joints.