Abstract: The ultrasonic energy could improve the appearance, microstructure and mechanical properties of TIG welded joint of aluminum alloy, when the weld pool was treated by the ultrasonic during TIG welding. In this paper, the effect of the methods of applying ultrasonic on appearance of welded joint of aluminum alloy was investigated. The results suggest that the continuous ultrasonic energy could result in a splash of melt in the weld pool and a pool appearance of welded joint. The discontinuous ultrasonic energy could avoid the splash of melt and a good appearance could be obtained. In order to obtain the discontinuous ultrasonic, the ultrasonic impact during welding and the ultrasonic input of rolling during welding could be used. The results suggest that both the weld penetration and weld width decreased when the ultrasonic impact was applied. The weld width decreases and the weld penetration increased when the method of rolling style was used, and the disadvantageous effect of mechanical impact on appearance could be removed.