A flushing mechanism includes a housing, an upper cover on the housing, a sleeve, a first piston, a first piston sealed module, a first piston loading spring, a second piston and a second piston loading spring. Wherein a pressure-relief and/or ejection-proof part is provided in the housing, the second piston sealed module are respectively provided surround the periphery of the bottom end and the central hole of the second piston. The bottom end of the second piston, the second piston sealed module and the lower end of the housing define an exterior lower cavity and an interior lower cavity used for cooperating with the second piston loading spring in course of drainage, sequentially the second piston are moved upward and the outlet is opened. A toilet bowl employing said flushing mechanism can reduce the flushing water consumption.