A leakage protective plug and a tripping mechanism thereof, comprising a housing, and a tripping mechanism and a conducting structure arranged within the housing, wherein the tripping mechanism comprises a restorable reset button, a tripping bracket, and a tripping coil and a pressing arm arranged in the tripping bracket, wherein the reset button is sleeved in the pressing arm in which a snap fitting mechanism is positioned such that the pressing arm and the reset button may be snapped together, and the pressing arm and the reset button may be disengaged under the control of the tripping coil. It has a simple and reliable structure, and avoids technical problems including poor contact of supply circuit and failure of power leakage protecting functions due to un-complete tripping which are resulted from the deformation of the tripping plate caused by the movement of the tripping iron core and by other external forces.