Four kinds of porous structures, copper wire mesh, metal foam, copper fiber sintered felts and cross-connected micro-channel plates were applied in a heat exchanger. Heat transfer coefficient per unit volume, pressure drop and comprehensive heat transfer effect of the heat exchanger were studied. The results show that: four kinds of porous structures can enhance the heat transfer performance obviously. The heat exchanger with copper metal foam has the largest comprehensive heat transfer coefficient which can reach 821.5W•m-3•K-1•Pa-1. And it increased about 2.5 times than that of the heat exchanger without porous structures. The comprehensive heat transfer coefficient increases with the flow rate in small case and decreases with the flow rate in large case. The coefficient reaches the largest value at the flow rate range of 6L/h-8L/h. The heat transfer coefficient per unit volume of the heat exchanger with four kinds of structures increases with the flow rate, and the increasing trend tends slowly. Metal foam of brass has the largest heat transfer coefficient per unit volume of 1266.8 W•m-3•K-1. Pressure drop increases with the flow rate, and the increasing trend tends rapidly. The 200 mesh copper wire mesh has the least pressure drop of 968.8Pa.