【Abstract】 Objective To study the expression level of nitric oxide synthase 1 (NOS1) in cervical cancer stem cells (CCSCs) and to explore the effect of NOS1on CCSCs sensitivity to Cisplatin (DDP) chemotherapy. Methods qRT-PCR was used to detect the expression level of NOS1 in cervical cancer cell lines. Cervical cancer cells with high expression of NOS1 were selected to culture CCSCs. Western blot was used to detect the expression of Nanog, SOX2, OCT4 stem marker protein and NOS1 in CSCs. MTS detects the IC50 value of cervical cancer cells and CCSCs for DDP. Control siRNA and NOS1 siRNA (si-NOS1) transfected CCSCs were divided into NC group and siNOS1 group. MTS detected the IC50 value of CCSCs in each group to DDP. Flow cytometry was used to detect apoptosis after treatment of CCSCs in NC group and si-NOS1 group by DDP, and the expression of ABCG protein and apoptosisrelated protein in cells was detected by Western blot. Results qRT-PCR results showed that the expression of NOS1 in cervical cancer cell lines was higher than that in human normal cervical epithelial cell line Hucec, and the highest expression was in HeLa cells (P＜0.05). OCT4, Nanog, and SOX2 stem cell markers were upregulated in CSCs (P＜0.05). NOS1 was upregulated in CCSCs (P＜0.05). MTS test showed that compared with HeLa cells, the IC50 value of CCSCs on DDP was increased. The MTS test found that compared with the NC group, the IC50 value of DDP of CCSCs cells in the si-NOS1 group was reduced. After CCSCs were treated with DDP, compared with the NC group, the apoptosis rate of si-NOS1 group was increased, ABCG2 and Bcl-2 expression were decreased, and Bax protein expression was increased (P＜0.05). Conclusion NOS1 expression is increased in CCSCs. NOS1 may reduce the sensitivity of CCSCs to DDP by upregulating ABCG2 to regulate apoptosisrelated proteins.