Abstract: In the process of maintenance or decommissioning of nuclear power plants, the high-pressure water jets are often used to remove the radioactive contamination from the site. Based on the conventional high-pressure water jet decontamination device, a proportional-integral-derivative(PID)-based electric adjustment control was proposed. The application of separate pressure and flow control in high-pressure water jet decontamination was studied. The results of theoretical analysis combined with decontamination laboratory verification show that: using the improved flow and pressure control methods, in the high-pressure water jet decontamination process, with the same other influencing factors, when a larger water flow rate is used to decontaminate, the decontamination factor is rather small, but this trend is tending to be gentle. Therefore, by adopting the improved high-pressure water jet decontamination device to achieve the same decontamination effect under the same pressure, the amount of secondary radioactive waste liquid generated can be significantly reduced, and this device is with high market application value.