In this paper,the welding residual stress of main weld-joint of the wind generator bracket was measured and studied. The butt joint of 40 mm-thickness Q345 D plate in actual working condition was prefabricated by using the MAG welding according to the qualified welding procedure specification of multi-layer and multi-pass welding. In the welding process,the 4 th,8 th and 12 th welded joint residual stress was tested by the blind-hole method. The test results show that the longitudinal residual stress reach peak area in the center of weld which is tensile stress,towards parent material tensile stress is gradually decreased,far away from the center of the weld residual stress is compressive stress. The transverse residual stress decreases from the peak of the tensile stress gradually.