Abstract: In pulsed GMAW,an obvious oscillation of dropolet will be excited at the electrode tip when the current is suddenly changed. Metal transfer can be precisely controlled by the utilization of downward momentum. Based on the analysis of the forces exerted on the droplet, an analytical model is developed to analyze the oscillation and detachment process of droplet and calculate quantitatively the effects of welding process parameters on the dynamic behaviors of metal transfer. The model can be used to guide the optimum design of welding process parameters in realizing one-droplet/one-pulse in pulsed GMAW.