A wheel assembly for an electric vehicle includes a wheel having a hub and an electric driving system for driving the hub. The electric driving system includes a driving device producing a driving moment. The hub defines an intra-hub space. The electric driving system further includes a speed reducer which is transmission-connected to a downstream side of the driving device and has a speed-reduction function. The electric driving system is coaxially connected to the hub, with at least a part accommodated in the intra-hub space.