The present invention discloses a toilet cover plate, an installation range adjustment mechanism and adjustment method of the toilet cover plate. The toilet cover plate comprises a hinging shaft which is arranged in a shaft sleeve at the rear end of the cover plate and is in rotary assembly matching with the shaft sleeve, wherein the hinging shaft is in plugging connection matching with a plugging shaft fixed onto a toilet body; the toilet cover plate further comprises a positioning component used for axially limiting the hinging shaft, wherein the positioning component is arranged between the shaft sleeve and the hinging shaft; and an adjusting portion which adjusts the axial position of the hinging shaft is located on one of the shaft sleeve, the hinging shaft and the positioning component or is located between any two components of the shaft sleeve, the hinging shaft and the positioning component. According to the toilet cover plate, the installation range adjustment mechanism and adjustment method of the toilet cover plate of the invention, the adjustment of the installation range of the cover plate can be realized through the installation range adjustment mechanism of the toilet cover plate, and the installation range of the cover plate can be realized with the position of the plugging shaft unchanged. The toilet cover plate has the advantages of more convenient operation, wider adjustment range and better universality.