This paper introduces an optimal design process for in-wheel interior permanent magnet synchronous motor (IPMSM) to achieve wide speed range. A finite element method (FEM) was used for calculating the inductances of the d-axis and q-axis by changing the structure of rotor shape in IPMSM. After FEM analysis, optimal design process to find optimal rotor shape is processed for wide speed range. In optimal process, the Kriging method based on the Latin hypercube sampling (LHS) and a genetic algorithm (GA) are applied due to suitability to non-linear data. Using this optimal design process, an optimal rotor shape is obtained. The optimal model has an increased wide speed range with reduced cogging torque.