The invention provides an MG53 (mitsugumin53) mutant and a preparation method thereof. The mutant is a serine-site mutant of MG53 protein in a Coiled-coil structural domain, and the mutant results in inactivation of MG53 phosphorylation. Meanwhile, the MG53 protein mutant can be used for preventing or treating diseases related to cellular membrane damage, such as diseases related to myocardial cell injury, diseases related to ulcer, trauma with a wound, particularly a difficult-to-heal wound, intestinal leakage, kidney injury and the like. The diseases related to myocardial cell injury can include one or more diseases related to following symptoms: myocardial ischemia, heart ischemia, heart ischemia/reperfusion injury, myocardial infarction, cardiac failure, arrhythmia and cardiac rupture. The diseases related to ulcer include one or more of following diseases: chronic ulcer, peptic ulcer, diabetic foot ulcer, diabetic foot gangrene and chronic gastric ulcer. Besides, the invention further provides a dry powder preparation, a spray preparation, a gel preparation and an emulsion containing MG53 or MG53 mutant as well as preparation methods of the preparations.