The utility model provides a forced ventilation device for railway tunnels. The forced ventilation device is composed of a railway platform lorry frame, two groups of axial flow fan matrixes arranged in tandem and positioned above the railway platform lorry frame, and a power distribution cabinet positioned at one side of an air inlet end of the axial flow fan matrix, wherein each group of the axial flow fan matrix comprises a fan support and six axial flow fans arranged on the fan support, the six axial flow fans are arranged to form a rectangular frame of which the shape is similar to that of the cross section of the tunnel. Compared with the prior art, the forced ventilation device for railway tunnels utilizes the axial flow fan matrix to enable an air exhausting surface to be completely distributed on the cross section of the tunnel, so as to ensure the air exhausting effect of the ventilation device in the tunnel; the forced ventilation device together with railway maintenance machinery can enter the tunnel or can enter the tunnel alone; the forced ventilation device is simple in structure and convenient to use.