The invention is suitable for the technical field of pipe fitting welding, and provides a pipe fitting welding stable butt joint device which comprises a device base and further comprises a moving mechanism, the moving mechanism comprises a first moving assembly and a second moving assembly, the first moving assembly is connected with a clamping mechanism, and the second moving assembly is connected with a lifting rotating mechanism; the lifting and rotating mechanism is fixedly connected with the centering mechanism; and the centering mechanism comprises a centering seat, a power piece, a second transmission module, a first rotating piece, a driving seat, a first threaded shaft, a centering assembly, an abutting piece and a limiting seat. According to the stable butt joint device for pipe fitting welding, through the moving mechanism, the lifting rotating mechanism, the clamping mechanism and the centering mechanism, centering butt joint of two sets of pipe fittings can be achieved, the central axes of the two sets of pipe fittings coincide, the perpendicularity of the pipe fittings after welding is guaranteed, the welding quality and efficiency of the pipe fittings are improved, and the production rejection rate of the pipe fittings is reduced; and the production economic cost is saved.