The invention discloses a zero-water-pressure system of a semi-automatic pulsator washing machine. The zero-water-pressure system comprises a washing machine body, wherein a water inlet is formed in one side of the upper end of the washing machine body and is connected with one end of a water inlet pipeline, the other end of the water inlet pipeline is connected with a switching device, a cylindrical switching cavity is formed in the switching device, one side of the cylindrical switching cavity is connected with the water inlet pipeline, the other side of the cylindrical switching cavity is in parallel connection with a water supply pipe and a pressurizing pipe, a rotating shaft is installed at the circle center of the cylindrical switching cavity, extends to the outside of the cylindrical switching cavity and is connected with an output shaft of a driving motor, and the driving motor is installed on the outer wall of the switching device. The zero-water-pressure system is novel in design, simple in structure, practical, convenient and quick, the problem that water cannot be injected for the washing machine due to insufficient water pressure is effectively solved, automatic water injection can be also completed even if the water pressure is zero, and the zero-water-pressure water injection purpose is achieved.