Abstract: To investigate the synergistic effect of cistanche phenylethanol side (PhGs) and glabridin (Gla) on skin pigmentation, the mass ratio of PhGs and Gla was screened by in vitro tyrosinase inhibition experiment,1, 1-diphenyl-2-trinitrophenylhydrazine (DPPH) free radical scavenging experiment and 2, 2-diazo-bis (3-ethyl-benzothiazole-6-sulfonic acid) diamiammonium cation (ABTS+) free radical scavenging experiment. The UVB-induced cytopigmentation model of B16F10 was further established, and the inhibition of melanin production was evaluated using tyrosinase activity and melanin content as indexes. The inflammatory model of HaCaT cells induced by lipopolysaccharide (LPS) was established, and the anti-inflammatory effect of the drug was evaluated by inhibiting the release of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The oxidative stress model of HaCaT cells induced by azodiisobuamidine hydrochloride (AAPH) was established, and the activity of superoxide dismutase (SOD) and catalase (CAT) was increased as indexes to evaluate the antioxidant effect of the drug. The optimal mass ratio of PhGs and Gla was selected by the above three cell models. The results showed that aqueous solutions of PhGs/Gla(1∶1), PhGs/Gla(5:1) and PhGs/Gla(10:1) prepared with m(PhGs):m(Gla) = 1:1, 5:1, 10:1 had good inhibitory and synergistic effects on tyrosinase activity and antioxidant activity. The inhibition rates of PhGs/Gla(1:1), PhGs/Gla(5:1) and PhGs/Gla(10:1) aqueous solutions at 0.4 mg/mL were 94.37%, 92.93% and 88.06%, respectively. The scavenging rates of DPPH free radicals were 89.44%, 88.72% and 88.10%, respectively. The scavenging rates of ABTS+ free radicals were 100.13%, 100.01% and 99.87%, respectively. When the mass concentration of PhGs/Gla was 25 μg/mL, PhGs/Gla(1:1), PhGs/Gla(5:1) and PhGs/Gla(10:1) aqueous solutions showed no cytotoxicity to B16F10 and HaCaT cells. The inhibition of tyrosinase activity in PhGs/Gla(1:1) aqueous solution was stronger (tyrosinase activity 23.80%), and the melanin content (30.90%) was significantly decreased. PhGs/Gla(1:1) aqueous solution had the best inhibition effect on IL-6 and TNF-α release, and the ability to enhance the activity of SOD and CAT. It showed good synergistic performance of the combination of PhGs and Gla, which was superior to single drug, and higher than PhGs/Gla(5:1) and PhGs/Gla(10:1) aqueous solution. The combination of PhGs and Gla plays a synergistic role in improving skin pigmentation by inhibiting melanin production, anti-inflammatory and antioxidant effects.