The invention provides a triggering mechanism of a life-saving device, comprising a shell, a driving assembly and a traction rope. The driving assembly comprises a handspike, a rotary rod, a thimble and a hook rod, wherein the rotary rod, the thimble and handspike are distributed in the shell in an n shape, one end of the thimble abuts on an air bottle, the other end of the thimble abuts on the side surface of the rotary rod, one end of the handspike is provided with a main spring, one end of the handspike abuts on one end of the main spring, the other end of the handspike abuts on the side surface of the rotary rod, the hook rod is arranged in the shell, a gemel is arranged at the long-edge end of the hook rod and provided with a booster spring at the outer side, the booster spring is parallel to the gemel, and one end of the traction rope is fixedly connected with a middle rotating shaft of the gemel. During the inflation, the rotary rod rotates by using the supporting shaft as a fulcrum to abut on the thimble, the thimble pierces the air bottle under the action of the rotary rod, and the air is released, thus the inflation of the life-saving device is completed so as to activate great power with smaller force.