As an important development direction of electric vehicles (EVs), the in-wheel motor powertrain has advantages of compact structure and flexible control, although there are some serious problems, such as high performance requirements to the drive motor and complex control strategies. To address these problems, a novel in-wheel tri-motor powertrain (IWTMP) is proposed at first, followed by the introduction of configuration and operating principles. Afterwards, vehicle power demand is calculated based on vehicle parameters and dynamic performance requirements, and a statistical analysis for typical driving cycles is carried out before conducting parameters matching for the IWTMP. Next, an optimisation for original parameters is achieved with an objective function of minimum total power of the IWTMP. Finally, a detailed IWTMP EV model is developed in CRUISE, and simulation results indicate that the IWTMP meets the dynamic performance requirements and efficiently reduces the energy consumption compared with an in-wheel single motor powertrain (IWSMP).