The present invention provides a hard-rock core barrel roller cutter assembly, which comprises a roller cutter and a saddle. The roller cutter comprises a base portion for operating, and a connecting portion integrated with the base portion and detachably connected to the saddle. The connecting portion has a butted oblique plane, and a width of the connecting portion is gradually increased from one end adjacent to the base portion to another end far away from the base portion. A fixing block is detachably connected to the saddle, and the fixing block has a pressure slope which matches with the butted oblique plane. A width of the fixing block is gradually decreased from one end adjacent to the base portion to another end far away from the base portion, and the saddle is muff-jointed out of the connecting portion and the fixing block. Comparing with the conventional technology, the roller cutter and the saddle of the present invention can be quickly assembled and detached, to improve the efficiency of the drilling operation. Simultaneously, the connecting strength thereof is high, and can satisfy the requirements of the drilling operation, and can be standardized.