The disposable bladder irrigator mainly uses the principle of gravity and pressure difference to flush the bladder, as follows: 1. gravity effect: the flushing bottle is usually hung above the patient's bladder. Gravity is used to make the flushing fluid flow naturally along the flushing catheter under the action of gravity, enter the catheter through the Y-type tee joint, and then flow into the bladder. Under the continuous action of gravity, the flushing fluid can stably enter the bladder to realize the flushing of the bladder. 2. pressure difference principle: when the flushing fluid enters the bladder, the pressure in the bladder will gradually increase. Because one end of the drainage catheter is connected to the bladder, the other end is in a lower position, and the external pressure is relatively low, under the effect of the pressure difference between the bladder and the external pressure, the washed liquid (including flushing fluid, urine and secretions in the bladder, etc.) will flow out of the bladder along the drainage catheter and enter the drainage bag through the Y-shaped tee joint. In this way, the bladder can be flushed by continuously flowing in and out of the flushing solution. In addition, during the flushing process, the opening and closing degree of the flushing catheter can also be adjusted through the regulator to control the flow rate of flushing fluid, and then adjust the flushing speed and pressure, so that the flushing process can more meet the specific conditions and medical needs of patients.