Duo to the shunt active power filter is widely used in the active power distribution system, more and more scholars aim to improve the compensation performance of the SAPF. The precise performance of the DC-link voltage is the key to ensure the SAPF be steady. Due to the bad performance of the output DC-link voltage based on the traditional PI controller, especially, under the load step-change and the reference voltage jump change, this paper presents an effective sliding mode variable structure control based PI control method in the voltage loop. At last, the simulations and experimental results show that the SMC based on PI scheme can improve the steady-state performance and transient response of the DC-link voltage, and reduce the bad affection of the DC-link voltage fluctuations. This work is supported by Science and Technology Project of China Southern Power Grid Co., Ltd. (No. GDKJXM00000015).