The invention relates to an underground mechanised continuous mining method. The method comprises the following steps: detecting components of ore materials of ore body on a working face, dividing anore mining surface of the working face into different lamellar areas according to quality grades of the ore materials, horizontally dividing the ore mining surface of the working face into one or moreworking sections, mining the working sections one by one from a starting end to a finishing end of the working face by using a drum type mining machine, mining areas one by one in each working section in a sequence from high to low according to the quality grades of the ore materials, only retaining the top lowest-grade ore materials and bottom steps in each working section, then enabling the mining machine to return to the starting end from the finishing end, and mining the top lowest-grade ore materials and the bottom steps of the working sections one by one at a time in the process. The underground mechanised continuous mining method provided by the invention is capable of respectively mining the ore materials with different qualities in the same working face; the mining profits are greatly increased; especially, the mining economy of hard materials with different quality grades is obviously improved.