This paper presents an identification method of parameters of induction motor which is driven by PWM voltage inverter. The method uses least square estimation based on the step voltage input and current response. Utilizing the fact that ratio of two characteristic roots is large in the induction motor circuit, we derived two 1st-order difference equations for direct computation of parameter values. experimental results are compared with conventional motor test results to demonstrate that the proposed method is capable of estimating parameters of induction motor at standstill.