The invention discloses a long-service-life MCrAlY coating, a preparation method thereof and application in a hot-end part, and belongs to the technical field of surface engineering. In the coating, Yand M are mainly present in the form of an intermetallic compound M5Y. The preparation method for the coating comprises the following steps: (1) preparing materials; (2) smelting, atomizing and pulverizing; (3) thermally spraying to prepare the MCrAl coating; (4) preparing an impregnation agent: preparing the impregnation agent from impregnation agent raw materials in proportion according to component requirements of the impregnation agent, and ball-milling, and mixing the prepared impregnation agent; and (5) performing rare-earth multi-element diffusion permeating: putting the impregnation agent and a part sprayed with the MCrAl coating into a vacuum oven, and performing high-temperature rare-earth multi-element co-permeation, thereby preparing the MCrAlY coating. The coating has the characteristics of being high in bonding strength, excellent in high-temperature oxidization resistance and excellent in thermal shock resistance, long in service life and the like, and can be widely applied to protection of engine high-temperature hot-end parts of the fields of aviation, ships and warships, electric power and metallurgy.