Abstract: A heat sink for a computer includes a base frame having a plurality of upright locating plates, each upright locating plate having pairs of locating flanges of triangular cross section symmetrically raised from two opposite lateral side walls at different elevations, and a Plurality of radiating fins respectively mounted on the upright locating plates at different elevations, the radiating fins each having a longitudinal mounting slot, which receives one upright locating plate of the base frame, and two longitudinal coupling flanges obliequely raised along two opposite lateral sides of the longitudinal mounting slot and stopped between two vertically spaced pairs of locating flanges at one upright locating plate of the base frame.