The invention discloses a nickel-metal hydride battery pack heat dissipation device for a hybrid electric vehicle, which comprises a box body. The front of the box body is provided with an air inlet, and the lateral surface of the box body is provided with an air outlet. The device is characterized in that a wedge-shaped air duct partition board is arranged at the lower part in the box body; a fixed support is connected to the middle upper part in the box body, and the fixed support is provided with a layer of battery monomers; the space above the layer of battery monomers is a space C through which the cooling air flows out, the space between the underside of the layer of battery monomers and the wedge-shaped air duct partition board is an electric element chamber B, and the space under the wedge-shaped air duct partition board is a cooling air inlet area A; and two sides of each battery monomer are provided with a strip groove and a buckle, the two adjacent battery monomers are connected through the buckles, and the strip grooves of the connected two battery monomers form a cooling gap. The device balances the flow passing through the battery monomers in the longitudinal and deep air direction of the air duct as much as possible so as to save the space and arrange the whole vehicle conveniently.