Abstract: A battery voltage measurement system is disclosed. The system includes a measurement unit, a calibration unit, and a control unit. The calibration unit is coupled between the measurement unit and a battery, for providing several test voltages to the measurement unit. The control unit is coupled to the calibration unit and the measurement unit, for controlling the calibration unit and for receiving an output voltage of the measurement unit. Under a calibration mode, the calibration unit outputs test voltages to the measurement unit, and the control unit calculates a calibration value according to a relation between the test voltages and the output voltage of the measurement unit. Under a measurement mode, the calibration unit transmits a battery voltage to the measurement unit, and the control unit calibrates the output voltage of the measurement unit according to the calibration value for acquiring accurate value of the battery voltage.