This thesis proposes the design of a novel power wheel with rim motor for an electric wheelchair. The novel electric wheelchair changes the driving structure of the traditional electric wheelchair equipped with reduction gears to one that is direct-driven by two rim motors. This design also provides the advantages of lower weight and more space. Full circle structure with good properties for damp-proof and dustproof .Long torque arm is supplied in hand-driven mode and high torque and torque density are supplied in the motor-driven mode. First of all, determination of the torque, speed and power based on dynamic evaluation. Secondly, Deciding proper tooth/pole combination, the magnetic circuit model is constructed. And then, the sensitivity analysis and optimal search method would be used. Finally, the optimal results would be demonstrated by the Finite Element Analysis (FEA). The magnet is modified to reduce the torque ripple. Some parameters of motor are adjusted to reduce the motor weight,and the performance of rim motor is achieved. The maximum torque is 35.6Nm, the maximum speed is 100 rpm, and torque density is 8.28Nm/kg. The power wheels with rim motor is integrated with lithium iron phosphate battery, brake system, and control as a compact assembly on wheelchair. This power wheel can be directly installed on commercial wheelchair frame and may become a new health and care product on the market. Both manual and power driving modes can be switched by users. After integrating to a new type electric wheelchair with rim motor, the total weight of wheelchair will only be half from the traditional one. This new type wheelchair can also bring users lots of advantages and conveniences to go further: Lightweight of the wheelchair, having folding function which can be accepted to put into a car easily.