Abstract: Based on ultrahigh frequency pulse gas tungsten arc welding process for stainless steel, appearance of weld and the influence of pulse current to flow in welding pool were carried out.The experimental results show that the welds penetration increased with the increasing of pulse frequency.When the pulse frequency f=80 kHz, the weld penetration rose by 24.6% at least with the depth increased by 88.7% at most.It could also be found that the width and depth of weld had the similar trend with the changed pulse frequency.Based on the data from experiments, the flow movement in the pool was investigated with effect of electromagnetic force to weld appearance and forced flow as the main purpose.