Abstract: A generating device of transverse rotating magnetic field with high-frequency modulation was designed.Carrier wave and modulating wave with high frequency were used to control the exciting current and frequency respectively.The magnetic field was applied to tungsten inert-gas arc welding in order to drive the arc rotate.For austenitic stainless steel 0Cr18Ni12Mo2Ti, the influence of magnetic parameters on appearance of weld was studied.The characteristics of arc instant shape in the magnetic field are analyzed. Based on acting zone of the base metal, the influence mechanism of rotating magnetic field on appearance of weld is discussed.The test results show that appearance of weld is effectively and simply controlled by the rotating magnetic field if magnetic parameters are properly setted, which can satisfy welding standard of different situations.