The invention discloses a control circuit of an energy-saving coil of an electromagnetic power switch. The control circuit is characterized in that a driving power supply sends a voltage-stabilizing circuit and a voltage detection circuit to a single-chip microcomputer for processing; the single-chip microcomputer outputs a pulse width modulation (PWM) signal and is connected to a solenoid coil of an energy-saving coil by a drive circuit. On the basis of the structure, the PWM technology is used for controlling electrification of the solenoid coil of the electromagnetic power switch, so that the usage amount of the enamelled wires can be saved and the coil energy consumption during the actuation period can be substantially reduced. Reliability of the control also can be improved.