To address the problems of poor bus voltage stability and slow system response when there are large disturbances such as PV output and load fluctuations in the optical storage DC micro-grid hybrid energy storage system, an improved sliding mode self-anti-disturbance control strategy that balances bus voltage stability and response speed is proposed. First, to address the problem of limited disturbance estimation capability of the first-stage observer, a second-stage observer is introduced for observation compensation, and the estimated value of the total disturbance from the cascaded observer is fed back to the controller for elimination. Second, to address the problems of slow response speed and poor robustness of the original non-linear controller, a non-singular fast terminal sliding mode control is designed for optimization, and the hybrid energy storage unit characteristics are used to compensate for the high and low frequency components to improve the system response speed. The stability of the designed controller is proved by Balbasin’s theorem and Liapunov’s criterion. Finally, the simulation is compared with other control strategies based on the Matlab simulation platform, and the simulation results verify the effectiveness of the proposed strategy.