The invention provides a low-grade clay mineral dry purification process. The low-grade clay mineral dry purification process provided by the invention comprises the following steps of (1) crushing low-grade clay minerals to obtain a crushed product; (2) conducting flash mineral grinding on the crushed product; (3) screening the product subjected to mineral grinding, directly draining sand in an oversize coarse-grain product and screening the oversize coarse-grain product to obtain an undersize product; (4) scattering the undersize product to obtain a scattered product; and (5) conducting grading on the scattered product to obtain a dry purification concentrate product. Through the dry purification process, the grade and recovery rate of the clay minerals in the dry purification product are effectively improved, the dry purification effect is obviously improved, and the use limitation of the dry purification process is reduced.