This paper mainly designs a terminal sliding mode controller (SMC) that can optimize the dynamic and static performance of the electric spring (ES) under the complex load environment on the user side, and improve the anti-interference ability of the ES. Firstly, the user-side ES-containing supply and distribution network (SDN) was modelled and analyzed, and then, the sliding surface and control rate was designed. Next, a reference voltage generation method was introduced, the stabilization conditions of the ES-containing SDN were identified, and the principles of parameter setting for the SMC were expounded. Finally, the proposed terminal SMC was proved feasible through simulations and dSPACE-based physical experiments and found to outperform the linear SMC in adaptability and dynamic and static performance.