This paper presents a superconducting magnetic energy storage (SMES)-based current-source active power filter (CS-APF). Characteristics of the SMES are elaborated, including physical quantity, coil structure, and priorities. A modified control is proposed and utilized in the SMES-CS-APF to simultaneously solve the harmonic issue produced by the nonlinear load, and mitigate the power oscillation under unbalanced voltage opera-tion. Finally, the effectiveness of the proposed SMES-based CS-APF is proved by simulation, and the superiority of using SMES is confirmed by comparison between SMES-CS-APF and bat-tery-based voltage source (VS)-APF. As compared, the pro-posed modified control is more suitable fitting with the SMES-CS-APF, due to its fast response and large power level.