Electrochemical impedance spectroscopy (EIS) is one of the most important parameters to evaluate the state of health (SOH) estimation and battery life. However, the measurement of battery’s EIS often occupies much time or requires specific large instruments. This paper proposes an online fast battery impedance measurement method. This method can measure the EIS of battery through three phase points at special frequencies. Thus, this method measures the EIS of battery in a short time. This method can filter out the noise through cross-correlation operation without interrupting the battery charging. This paper verifies this method is rational by simulative experiment with PISM.