The present invention provides an electronic device heat radiator with an arc-shaped cross section. The heat radiator comprises a base body and pins at the t the periphery of the base body. The cross section of the base body is an arc shape. The fins comprise a first fin and second fins. The first fin extends outward from the center point of the arc shape and is perpendicular to the arc. The second fins comprise a plurality of fins which extend outward from the surface where the arc line of the arc shape is and a plurality of fins which extend outward from the first fin. The second fins which extend to the same direction are parallel to each other. An isosceles arc is formed by the extending end parts of the first fin and the second fins. The surface of the bottom side of the arc and the heat radiator of an electronic device are subjected to thermal contact. According to the electronic device heat radiator, the structure of the heat radiator is optimized, and the heat radiator structure is set according to the heat distribution rule to maximize heat radiation efficiency.