The utility model relates to a rotary-piston-type underground water plugging device which is composed of a battery, a control circuit, a pressure sensor, a driving motor, a piston sleeve, a rotary piston, a one-way valve, a lower connector, a connector, a control cabinet short section and an oil pipe. The lower connector is sequentially connected with the connector and the oil pipe through threads, a center groove is formed in the upper portion of the lower connector, a liquid inlet channel communicated with the center groove is formed in the side wall of the lower connector, and the one-way valve is installed in the liquid inlet channel. The piston sleeve is installed in the center groove of the lower connector through threads, and a liquid inlet and a liquid outlet are formed in the side wall of the piston sleeve. The rotary piston is in a cylindrical structure on the whole, a hole shrinkage section is arranged in the middle of the rotary piston, a piston sleeve ring is formed between the hole shrinkage section and the inner wall of the piston sleeve, a piston liquid inlet groove is formed in the lower end cylindrical face of the rotary piston, and a first limiting piece and a second limiting piece which are distributed at 90 degrees are arranged on the lower portion of the rotary piston. A first limiting groove and a second limiting groove which are distributed at 180 degrees are formed in the piston sleeve corresponding to the limiting pieces of the rotary piston.