The invention discloses a gear and lever mechanism of an electric detector for filter screens of purifiers. The gear and lever mechanism comprises a base and a framework. The framework is arranged on the base, a clamping block for accommodating the filter screens is arranged on the base, a sliding seat is arranged on the framework and is slidably connected with a vertical measuring rod, the measuring rod is arranged right above the clamping block, a rack is fixed onto the measuring rod, a first gear which is meshed with the rack is hinged onto the framework, a sector gear is fixed onto the first gear, an oblique lever is arranged below the sector gear, a second gear which is meshed with the sector gear is hinged onto the lever, a tension spring which is fixed onto the framework is connected with one end of the lever, a sector block is arranged at the other end of the lever, and a first connecting rod and a second connecting rod are respectively butted onto the sector block and are hinged onto the framework. The gear and lever mechanism has the advantage that problems of complicated integral structure, high price and low detection efficiency of an existing electric detector for filter screens can be solved by the aid of the gear and lever mechanism.