Electronic components and equipment dissipate large amounts of heat when working, which have effects on the thermal reliability of electronic components and equipment. This article numerically analyzes the fin heat sink using Icepak software, and calculates the flow field inside the radiator fins and temperature fields, to obtain the temperature of the key elements of back finned heat sink. The effects of three factors of fan air flow, fan location, fin thickness on the back fin heat sink. It is concluded that the temperature was reduced with the increased amount of wind; the temperature varies with the different position of fan and fan thickness.To summarize, the optimal parameters for reducing back finned heat sink which include three fans, 0.005 kg/s of fan air flow, 0.002m of fin thickness. In addition, the optimized results were analyzed.