This paper proposes a new approach to achieve on-line identification of the q-axis inductance in the interior permanent magnet synchronous motor (IPMSM) based on the current norm characteristics. Based on the proposed identification method. The d-axis current depends on the mismatch of Lq, and the value of the d-axis current is obtained message of inductance of Lq. Using a simple method to assuming the zero point of the d-axis current, it is possible to achieve the on-line parameter identification. This paper describes an improved technique to identify the motor parameters, which introduces a P controller and a PI controller to the current control system of the IPMSM. Identification characteristic is examined through computer simulations.