For the optimal design of a heat exchanger network,the inlet and outlet stream temperatures of each heat exchanger in the network should be known.An explicit analytical solution of stream temperatures of an arbi-trary connected heat exchanger network was introduced,which is suitable for the thermal calculation of heat ex-changer networks.For the heat exchanger network synthesis,this solution was further developed and coupled with the stage-wise superstructure heat exchanger networks.The new calculation procedure reduced the computer mem-ory requirement dramatically.On the basis of this solution,a mathematical model for synthesis of heat exchanger networks with genetic algorithm was formulated,which is always feasible and no iteration is needed.Two examples were calculated with the proposed approach and better results were obtained.