Abstract: By combining the classical Mayr and Cassie equations, a hybrid arc model for pulsed TIG welding was developed, and an equation of the arc damping factor for the hybrid model is formed by analyzing the actual arc physical process. Selecting principle of the parameters of the arc damping equation was provided. The estimation of the parameters for the hybrid model was also discussed, and the parameters were given according to the actual arc process. The hybrid model was tested both in static arc characteristic and dynamic arc characteristic with different frequencies. The results show that the hybrid arc model could precisely express the V-I characteristic of the arc in pulsed TIG welding process.