Thermal analysis of new designed heat-sink models was carried out according to the natural ana the forced convection using computational fluid dynamics(CFD). Heat resistance of wave type, top vented wave type and plate type of heat sink was compared with each other As the direction of fin and air flow are vertical(z-axis), it is shown that radiant heat performance of all of heat sinks was superior than other experimental conditions. Especially, the heat resistance of top vented wave heat sink was $0.17^{circ}C/W$(forced convection) and $0.48^{circ}C/W$(natural convection). The radiant heat performance of heat sink was increased with increasing the height of fin and the width of fin pitch.