The present invention provides an electronic device heat radiator with a triangular cross section. The heat radiator comprises a base body and fins at the periphery of the base body. The cross section of the base body is an isosceles triangle. The fins comprise first fins and second fins which extend outward from the apex angle of the isosceles triangle. The second fins comprise multiple fins extending outward from the surface of the two waists of the isosceles triangle and multiple fins extending outward from the first fins. The second fins extending to the same direction are parallel to each other. The extending end parts of the first fins and the second fins form a second isosceles triangle. The surface where the bottom of the isosceles triangle is and the heat radiation body of the electronic device are in thermal contact. According to the electronic device heat radiator, the structure of the heat radiator is optimized, the heat radiator structure is set according to a heat distribution rule, and the heat radiation efficiency is maximized.