State of charge(SOC) is one of the important parameters that reflects battery usage. In the actual work process of lithiumbattery, the drift current measured by current sensor will have great influence on the accuracy of SOC estimation. For this problem, the Drift-Ah integral method is proposed with drift current, the noise combination model is established, and the SOC estimation of lithium battery is achieved by using the cubature Kalman filter(CKF). Finally, the simulation experiment of lithiumbattery is carried out. Simulation results show that the proposed method can effectively suppress disturbance of drift current, with the advantages of high filtering accuracy and low complexity.