As the market share of the electric vehicles (EV) raises, the driving range has become one of critical concerns for the EV. Except for the battery system, improving the efficiency of motor system is also one of the effective methods. Amorphous alloy (AA) material are characterized by lower iron loss and lower saturation magnetic flux density, result in higher efficiency of AA motors compared to conventional machines. However, the efficiency of AA motor becomes lower due to the need for a larger excitation current during heavy load operations. To address this issue, the paper proposes an immersive design methodology, and an 18 kW EV drive motor is illustrated as an example. The research in this paper optimizes the design of AA motors under heavy load conditions. Lower cost and higher efficiency can be achieved with the proposed design methodology. Thus, the higher efficiency of AA motors can be sufficiently performed and effectively improves driving range of EVs.