A loose-proof structure of a filter cartridge shell, includes: a filter cartridge shell body, the filter cartridge shell body has an open end which includes several treads in its inside and an upper end surface, and an upper end cover, which is hermetically and spirally coupled with the filter cartridge shell body. The upper cover has a raised rafter edge. The raised rafter edge and the open end are equipped with a loose-proof fixed ring. a periphery surface of the raised rafter edge has loose-proof locking teeth, an inside surface of the loose-proof fixed ring has loose-proof tooth spaces matching with the loose-proof locking teeth. An external end surface of the open end has loose-proof scabs, the loose-proof fixed ring has loose-proof grooves on its bottom matching with the loose-proof scabs.