The invention relates to a tube type heat exchanger, in particular to the tube type heat exchanger and application of the tube type heat exchanger in a direct alcohol fuel cell system. In the invention, foam metal is used as a heat exchanging sheet outside the tube of the heat exchanger and connected with a corrosion resistance tube through welding, sticking, swelling connection and other connection manners, air is used to condensate water vapor discharged by a fuel cell, and the liquid level or the air humidity in a solution mixing cavity is used to control the on/off of a cooling fan, thereby achieving the water-heat balance of the direct alcohol fuel cell system. Compared with the prior art, the method is beneficial to maintain the water-heat balance of the fuel cell system under the variable ambient humidity conditions; and the heat exchanger has high heat exchange efficiency, small volume and light weight, is beneficial to improve the integrated level of a system, is suitable for emergency supply, electronics supply and power source which demand high energy.