The invention relates to a device for preventing self-discharge of a zinc-manganese dry cell. The device is technically characterized by comprising a controllable insulating plate, a fixed insulating plate, a control switch, an electromagnetic relay and a single chip control module, wherein the controllable insulating plate and the fixed insulating plate surround an electrolyte to form an insulation device and also separate the electrolyte from a zinc tube; the control switch is fixedly mounted together with the controllable insulating plate; the electromagnetic relay is mounted at the lower end of the control switch; the single chip control module is connected with the control switch and the electromagnetic relay, respectively. The device for preventing self-discharge of the zinc-manganese dry cell is reasonable in design; as the insulation device is additionally arranged between the electrolyte and the negative electrode (namely the zinc tube) and controlled by the single chip control module, the probability of self-discharge of the ordinary zinc-manganese dry cell can be effectively lowered, the service life of the cell can be prolonged and electric energy can be saved. The service life of the zinc-manganese dry cell with the device is obviously longer than that of a commonly placed zinc-manganese dry cell, and therefore, unnecessary waste can be reduced.