The invention provides a cooling fan for an engine of a motor 
train unit. A method for combining a traditional one-dimensional 
heating power design with three-dimensional numerical 
simulation is adopted to perform the pneumatic design for an 
impeller of a centrifugal cooling fan for the engine of the motor 
train unit; the cooling fan for the engine of the motor 
train unit mainly consists of an 
impeller and a casing, wherein the 
impeller is a main part of a 
centrifugal fan, and the impeller adopts an inclined wheel disc, so that the consideration is given to high flow and high full pressure, the streamline form in the impeller is more accordant with the flowing characteristics, and the flowing loss is reduced; an inlet fairing is additionally mounted on a wheel hub, so that the air flowing condition in an inlet of the impeller is improved, and the 
noise of the fan caused by the inlet 
impact is reduced; and the increment of the blade length is equal to increase the effective acting area of single blade, so that the number of blades is decreased, the 
cascade solidity is decreased, and the impeller 
machining difficulty is reduced. Compared with an import fan with the same type, the fan is largely improved in performance; and under the conditions of invariable shape and size and reduced rotating speed by 25.5%, the full pressure is increased by 11.8%.