<p>In this paper fixed-time distributed equalization control is proposed for the SOC of lithium battery based on a finite-time disturbance observer. At the physical layer of the system, the influence of frequently changing charge and discharge current disturbance on the equalization result is considered, an equalization system model with disturbance is established, and a finite-time disturbance observer is constructed to estimate the disturbance. At the information layer of the system, the lithium battery pack is regarded as a multi-agent system. A fixed-time distributed cooperative control law is designed, so that the SOC of each single lithium battery can be consistent within a fixed-time. The stability proofs of disturbance observer and closed-loop system are given. According to the simulation results, the effectiveness of the method is verified in the charging mode and the discharging mode.</p>