Abstract: In this paper the influence of the continuous ultrasonic (CU) and pulsed ultrasonic (PU) on GMAW short circuiting transfer and weld appearance was studied. The results revealed that the continuous ultrasonic and pulsed ultrasonic could improve the short circuiting transfer process and weld appearance. The effect of the continuous ultrasonic on droplet transfer cycles was consistent with that of the pulsed ultrasonic. The effect of the continuous ultrasonic on weld appearance was more significant than that of the pulsed ultrasonic. The results showed that the droplet transfer cycles of GMAW, CU-GMAW and PU-GMAW are 86.5 ms, 79 ms and 76.5 ms, repectively. The weld width and weld penetration of GMAW is 5.06 mm and 0.361 mm. Compared with the GMAW, the weld width reduce 0.4 mm and the weld penetration increased by 100% in the CU-GMAW, the weld width reduce 0.19 mm and the weld penetration increased by 67.7% in the PU-GMAW.