Aluminum plate fin heat exchanger is made by tightly placing corrugated metal heat conducting fins between several layers of flat metal plates, and adding seals around each layer. It is welded as a whole in a salt solution furnace at a temperature of nearly 600 ℃. The main function of fins is to enhance heat transfer, and also to strengthen the strength of two metal plates. In this type of heat exchanger, some of the heat exchange between adjacent channels is transferred through flat plates, but the vast majority of the heat is transferred through corrugated fins. Because there are corrugated fins between the plates, the heat transfer area is greatly increased, so its heat transfer area per unit volume is more than 10 times larger than that of a general tube heat exchanger, reaching 4000-5000m2/m3. By combining different channels, heat exchangers in the form of counterflow, cross flow, etc. can be obtained. It has the advantages of large heat transfer area per unit volume, high heat transfer efficiency, low fluid resistance, small heat capacity, compact structure, and allowing multiple media to exchange heat simultaneously.