The invention discloses a heat transfer printing method of metal condensation tanks. The heat transfer printing method comprises the following steps: 1) patterns to be transferred are confirmed and then plate making is carried out, and after a plate is made, a heat transfer printing film is printed, wherein before the plate making, a release position is adjusted to a position after improvement from a position before the improvement; 2) the metal condensation tanks are preheated, and are parallelly placed in a hot blowing furnace for preheating; 3) the preheated metal condensation tanks are taken out of an assembly line and are subjected to heat transfer printing; and 4) the metal condensation tanks after the heat transfer printing is completed are subjected to pattern strengthening. A rubber plate extension section is arranged at the rear section of the heat transfer printing film, so that the length of the heat transfer printing film is increased, and the heat transfer printing method is simple and easy to implement. Different patterns are transferred to the surfaces of the metal condensation tanks, so that the identification and forgery prevention are convenient for users; in addition, a heat transfer printing film technology is used, heat transfer printing film patterns are transferred to the metal condensation tanks, and the patterns are not prone to fall off or fade and have brilliant colors, thus the aesthetic quality and the forgery prevention property of the metal condensation tanks are improved; and no 1-2mm visible overlapped seam is generated at a joint, thus the metal condensation tanks are attractive and do not have overlapped printing seams.