The invention discloses a preparation method of a membrane electrode of a fuel cell. The method comprises the steps of coating a transfer medium with a substrate layer; carrying out in-situ reduction-deposition of platinum nanoparticles on the substrate layer and then coating the platinum nanoparticles with a layer of proton conducting polymer to form an electrode catalyst layer; and finally transferring the catalyst layer to a proton exchange membrane by adopting a heat transfer process to prepare a membrane electrode. The invention further discloses the membrane electrode of the fuel cell and an application of the membrane electrode on a cathode or an anode of a proton exchange membrane fuel cell. The problem of contradiction between reduction time and electrochemical active area in thein-situ deposition process of platinum is relatively well solved and the yield of heat transfer is improved. The membrane electrode has the beneficial effects of high catalyst activity and utilizationrate, large electrochemical active area, low gas transmission impedance in the catalyst layer and the like, and is low in production cost, simple and fast in process and high in yield, and massive production is easy to implement.