In order to study iron loss distribution characteristics in stator and motor of induction motor, an improved iron-loss model with higher accuracy is proposed based on time-stepping finite elements. In Section Two,various iron loss formulaes are compared. followed by an miproved iron-loss model. In Section Three,the time variation of flux density and loci of lux density at different core locations are firstly analyzed, then the iron loss distributions in different areas in the core were concluded. It is found that , in stator side, iron losses mainly distributed at the boundary between teeth and yoke, in yoke, as well as in tooth bodies; Meanwhile, at rotor side, the iron loss in the in the tooth top area is clearly due to high harmonies. In Section Four, the validity of this novel formulation is confirmed by experiment. The experimental and calculated losses are found to be in good agreement. It is clarified that the proposed method is useful for the accurate estimation of iron loss of induction motor. I. INTRODUCTION Premium efficient motor applied in electrical vehicle can further reduce the energy losses. In the process of the development of premium efficient induction motor, more accurate iron-loss model is needed. It is well known that the magnetic field in induction motor includes many high- frequency harmonics,for instance, slot harmonics by the stator and rotor, and carrier harmonics by pulsewidth modu lated inverters. Estimation of these harmonic iron losses is essential during the machine design. In this paper, an improved iron-loss model with variable coefficient is established. With the model we need predict accurately the iron loss distribution and search for the region with large potential for reducing core loss. By optimizing the core structure and other measures to achieve the purpose of decreasing the loss and improving the efficiency of the motor. The magnetic field in induction motor is complex, where alternating, rotating and harmonic magnetic field mutual influence, so the prediction of iron losses is still an open research filed. At present, there are lots of iron losses calculation models, but lacking of comparison and analysis of different models. Two missions need to be done in this paper: 1) An improved variable coefficient orthogonal iron-loss model with the revised hysteresis losses is proposed. 2) Using the improved model, we analysis the regularity of core losses distribution for laying a foundation to the research