The invention discloses an impervious geosynthetic clay liner, and belongs to the technical field of waterproof coiled materials. The impervious geosynthetic clay liner comprises a woven cloth layer (1), a buffer layer (4), a bentonite layer (2), a buffer layer (4) and a non-woven cloth layer (3) from top to bottom, wherein the bentonite layer consists of the following raw materials of, by weight,80-100 parts of modified bentonite, 10-20 parts of adhesive, and 30-40 parts of water; the adhesive is formed by mixing polyvinyl alcohol solution and water glass; the buffer layer is mixed liquid prepared by dissolving agar and vital gluten into the water; and the mixed liquid is preheated to spray into organic solvent for standing and layering to prepare gel beads. The impervious geosynthetic clay liner achieves excellent characteristic of impervious performance, and is broad in prospect and application value in the field of the waterproof coiled materials.