Magnetic needle magnetic grinding technology, as a kind of surface finishing technology, has the advantages of good flexibility and adaptability. Besides, it can also conduct finishing process on small parts, complex outer surfaces and inner surfaces of pipes. Due to the existence of defects such as oxide scale at the weld joints, the service performance of the parts is seriously affected. This article uses vibration assisted magnetic needle magnetic grinding technology to grind welded pipe fittings, and explores the effect of removing oxide scale on the weld surface and the improvement of the residual stress state, which provides a new method for weld surface treatment.