A wheel system with bidirectional input and one-way output includes a unidirectional transmission device respectively installed between a first driving rotating directional input wheel set and a bidirectional input shaft, between a first driving rotating directional output wheel set and a constant rotating directional output rotation part, and between the constant rotating directional output rotation part and the bidirectional input shaft, thereby preventing the first rotating direction transmission wheel set from being coupled to and generating a power transmission dampening effect while being driven in the second driving rotating direction.