Abstract: ob＜x＞jective To explore the effect of melatonin on endometrial stromal cells (ESC) in endometriosis and its possible mechanism. Methods The eutopic endometrial tissues of 13 patients with endometriosis were collected for primary isolation and culture of mesenchymal cells. CCK-8 was used to detect cell viability; Transwell experiment was used to detect cell migration and invasion; qRT-PCR was used to detect the ex＜x＞pression of FGA mRNA in cells; Western blot was used to detect the ex＜x＞pression of Keratin, Vimentin, Slug, FGA, p-FAK, FAK, p-AKT, AKT and MMP-2 protein in cells. Results The ESC cells were successfully isolated and cultured. Compared with the blank control group, after treating ESC cells with 0.25 mmol/L, 0.5 mmol/L, and 1 mmol/L melatonin, the cell viability, cell migration and invasion numbers were significantly reduced (P＜0.05), and the ex＜x＞pression of Keratin protein was obvious increased (P<0.05), the ex＜x＞pression of Vimentin, Slug, FGA, p-FAK/FAK, p-AKT/AKT and MMP-2 protein was significantly reduced (P<0.05), and the effect of melatonin on ESC cells showed a dose dependence. Compared with the blank control group, ESC cell viability, cell migration and invasion numbers in the melatonin group were significantly reduced (P＜0.05), and the ex＜x＞pression of Keratin protein was significantly increased (P＜0.05), the ex＜x＞pression of FGA mRNA and Vimentin, Slug, FGA , P-FAK/FAK, p-AKT/AKT and MMP-2 protein ex＜x＞pression were significantly reduced (P＜0.05); Compared with the melatonin group, there was no statistically significant difference in the indexes of the melatonin+oe-NC group (P>0.05); Compared with the melatonin + oe-NC group, the cell viability, cell migration and invasion number of the melatonin + oe-FGA group were significantly increased (P<0.05), and the ex＜x＞pression of Keratin protein was significantly reduced (P<0.05), the ex＜x＞pression of FGA mRNA and protein ex＜x＞pression of Vimentin, Slug, FGA, p-FAK/FAK, p-AKT/AKT and MMP-2 were significantly increased (P<0.05). Conclusion Melatonin may inhibit ESC cell migration, invasion and epithelial-mesenchymal transition by inhibiting FGA-mediated FAK/AKT/MMP-2 pathway activation, thereby inhibiting the progression of endometriosis.