The invention discloses a trigger switch with a power failure restart protection function, which mainly comprises a base body (1), a shell (2), a trigger (3), a lock knob (4), a magnetic yoke (19), a coil (20), a magnetic core (22) and an armature (23), wherein the base body (1), the shell (2), the trigger (3), the lock knob (4) and related structural elements form a mechanical structure part of the switch, and the magnetic yoke (19), the coil (20), the magnetic core (22), the armature (23) and relates electromagnetic elements form the electromagnetic structural part of the switch. The trigger switch formed by the mechanical structural part and the electromagnetic structural part can realize closed locking after the switch is switched on and the off functions of the switch when power failure occurs suddenly, and if the switch is expected to be switched on again, the trigger is required to be pressed again to realize the power failure restart protection function of the switch. The invention has compact structure and low manufacture cost, is suitable for large and middle sized angular finishing grinders, polishing machines, waxing machines and other electric tools, and accords with the national safety standard.