Abstract: For HPVP-GTAW welding, the weld forming characteristics of 2A14-T6 aluminum alloy was evaluated, and the effect of ultrahigh frequency pulse square-wave current parameters on weld formation was investigated as well.The experimental results indicated that, compared with traditional variable polarity GTAW, the application of ultrahigh frequency pulse square-wave current can improve the weld penetration and the weld formation.When the amplitude and the ratio of pulse current are fixed, pulse frequency can significant affect the weld formation.Keeping the RMS of positive current unchanged approximately with permissible variation of ±5A, increasing the pulse current frequency and amplitude as well as decreasing the pulse current duty cycle within a certain range have an evident effect on enhancing the weld penetration of aluminum alloy in HPVP-GTAW process.