Abstract: This paper studies the relationship between i_fd/I_f(t),and the spattering rate under different continuous time period of short circuiting on welders with different dynamic characteristics.On the theoretical basis,this paper analyses the causes affecting the spattering rate from two welders with different dynamic characteristics and proposes that i_(fd)/I₍₁₀₎ can be used as a new general parameter to evaluate the dynamic characteristics of many kinds of are welders.A mathematic model of the relationship between spattering rate and i_(fd)/I_f(10),proved to be true within an accuracy of 1.5%,has been established as well.