Abstract: An optimization method of diffusion cooling with two layers porous matrix was presented in this paper.Coolant was injected into the solid matrix under certain differential pressures and characteristic sizes of the porous matrix.With the variation of the porous material,porosity and thickness ratio,the minimum temperature of the hot surface is ultimately subject to cooling optimization when the global constraint conditions of mass and cost,etc,are satisfied.In this paper,the genetic algorithm was used to find the feasible optimization design with the analytical solution of one-dimensional LNTE model.The results show that the porosity of the porous plate close to the coolant reservoir should be as large as possible,but this phenomenon is not correct on the porosity of the porous plate close to the hot surface,its value depends on the balance of effects on the effective thermal conductivity,heat convective coefficient and coolant mass flow rate.