The invention discloses a self-expanding cable conduit sealing plug. An objective of the invention is to provide a self-expanding cable conduit sealing plug which is convenient in operation, low in labor intensity, good in sealing effect, and convenient in dismounting, and can be reused. The self-expanding cable conduit sealing plug comprises a disc-shaped chassis, a disc-shaped platen, and an elastic sealing sleeve. The end face of the disc-shaped chassis is provided with a connecting screw rod. The connecting screw rod is provided with a locknut. The disc-shaped platen is provided with a connecting screw rod via. The elastic sealing sleeve is between the disc-shaped chassis and the disc-shaped platen. The connecting screw rod passes through the elastic sealing sleeve and the connecting screw rod via. The locknut and the elastic sealing sleeve are on two opposite sides of the disc-shaped platen.