Circuits and methods for measuring a working current of a circuit module. An exemplary circuit for measuring a working current of a circuit module includes a capacitor. The capacitor supplies a voltage to the circuit module using a voltage on the two terminals of the capacitor. The circuit also includes a voltage measuring module. The voltage measuring module measures a voltage change amount on the two terminals of the capacitor in an unit time. The working current of the circuit module is determined by the circuit according to the voltage change amount on the two terminals of the capacitor in the unit time and a capacitance of the capacitor.