Based on Newton law of viscosity and computational fluid dynamics (CFD), on the basis of the actual project, it explores the cooling performance of finned radiators with five different vertical sections under the condition of forced convection. According to their respective heat dissipation performance and economy, the optimum vertical cross section shape of the fin type radiator is selected to be the triangular section. Compared with the traditional rectangular fin radiator, its heat dissipation performance is improved by 4.23% and the material cost is reduced by 17.95%.