The invention discloses a closestool flushing method. The method comprises the following steps that 1, a flushing signal generated due to starting of a user is received through a control unit; 2, the control unit starts a valve unit, and a cleaning pipeline of a closestool is kept in a water-running state for T1 seconds; 3, after the cleaning pipeline is kept in the water-running state for T1 seconds, the control unit controls the valve unit, so that the valve unit stops water supply to the cleaning pipeline, and meanwhile a jetting pipeline of the closestool is kept in the water-running state for T2 seconds; 4, after the jetting pipeline is kept in the water-running state for T2 seconds, the control unit controls the valve unit, so that the valve unit stops water supply to the jetting pipeline, and meanwhile the cleaning pipeline is kept in the water-running state once more for T3 seconds; 5, after the cleaning pipeline is kept in the water-running state once more for T3 seconds, the control unit switches off the valve unit to end a flushing control program. By the adoption of the flushing steps, the flushing procedure is operated in a phased mode, the good siphon effect can be generated, water can be saved to a certain extent, in particular, the flushing performance at the time of low pressure is improved, and the method is simple, feasible and obvious in effect.