The invention discloses a control system for a cooling fan of a traction motor of a locomotive, belonging to the technical field of locomotive control. In the invention, operating current of the traction motor is used for controlling revolving speed of the cooling fan of the traction motor, and a current sensor is added in a DC/AC main inverter, so as to connect the current sensor with a main inverter controller of the DC/AC main inverter. By using the control system for the cooling fan of the traction motor of the locomotive, the revolving speed of the cooling fan of the traction motor can be controlled precisely in short time, the auxiliary power consumed by the cooling fan of the traction motor can be greatly reduced, and the maintenance of the whole system is more convenient.