The invention discloses a method and device for controlling a motor train unit to deice and a motor train unit. The method comprises the following steps of detecting the current working state of the motor train unit when the motor train unit receives a snow resistant braking instruction; judging whether a braking parameter of the motor train unit satisfies a preset braking condition or not when the current working state of the motor train unit is a traction working condition; and controlling to apply braking forces to braking discs of any one or more marshaled vehicles included in the motor train unit when the braking parameter of the motor train unit satisfies the preset braking condition. According to the invention, a technical problem that the motor train unit cannot be controlled to remove the ice and snow in time because a scheme for removing ice and snow between braking clamp disc sheets of the motor train unit in the prior art can only act upon the braking working condition is solved.