Provided is a wheel-tread-changeable mobile robot platform. The wheel-tread-changeable mobile robot platform mainly comprises a chassis, wheels, a telescopic mechanism, a driving mechanism and a transmission mechanism, wherein the telescopic mechanism, the driving mechanism and the transmission mechanism correspond to the chassis and the wheels. Other parts of a robot such as a trunk, a support and a lifting mechanism can be installed on the platform. The wheels comprise a driving wheel, a driven wheel and an auxiliary wheel. A wheel tread refers to the distance of one wheel on the platform relative to other wheels or relative to a certain reference point or a certain reference line on the chassis. The wheel tread of the platform can be changed when the platform is static and can also be changed when the platform walks. The wheel tread of at least one or more than one wheel on the platform can be changed. The wheel tread of one wheel can be changed independently, and can also be changed coordinately with the other wheels.