The invention relates to a cordless curtain, in particular to a transmission stop device for a cordless curtain. The technical scheme provided by the invention is that the transmission stop device for the cordless curtain comprises a box body, coiled torsion springs arranged in the box body side by side and a plurality of torque wheels arranged side by side and mutually meshed with one another; at least one stop wheel capable of transversely moving back and forth along the box body is arranged at each of the two transverse ends of the box body; a rotation stop assembly is arranged between the stop wheel and the box body. With the adoption of the technical scheme, the transmission stop device for the cordless curtain, provided by the invention, has the advantages that the situation that the curtain cannot completely hang down or put away is avoided, the production cost is reduced, and the structure is simple.