Abstract: A novel modeling method of T-S fuzzy system for an affine nonlinear system is proposed. Based on this method, the responses of T-S fuzzy system is the same as the original nonlinear, the modeling error is avoided compared with the linearization method around the equilibrium points, and this method can be applied the nonlinear system contained the multiple nonlinear terms. T-S fuzzy model of GMAW system is established, the response characteristics of the T-S fuzzy system are not changed compared with the nonlinear GMAW system. The simulation result proves the validity of this method.