Breast cancer is the most common gynecologic tumor globally that threatens women's health. Lipoic acid is a type of antioxidant that can alleviate oxidative stress damage. Studies showed that lipoic acid could inhibit the proliferation of tumor cells in cervical cancer and colon cancer. This paper intends to explore the combined effect of lipoic acid and paclitaxel on breast cancer cells. Breast cancer MCF-7 cells were divided into four groups: control group, lipoic acid group, paclitaxel group, and a combination group. MTT was applied to detect the drugs' influence on breast cancer cell proliferation. A colony formation test was used to determine the effects on breast cancer cell clone formation rate. Western blot was performed to detect the effects on nuclear factor (NF)-κB. Lipoic acid alone can inhibit tumor cell proliferation and clone formation with time dependence. Compared with the control, paclitaxel alone can significantly suppress tumor cell proliferation and clone formation (P < 0.05). Lipoic acid and paclitaxel in combination obviously strengthened their individual inhibitory effects on tumor cells (P < 0.05). Compared with the paclitaxel alone group, the combination group exhibited more remarkable inhibitory effect (P < 0.05). Lipoic acid alone or combined with paclitaxel can inhibit NF-κB expression and inhibit breast cancer cell proliferation.