Objective To explore the association of gestational diabetes mellitus （GDM）complicated with hypertensive disorder during pregnancy（HDP）with cesarean section and pregnancy outcome. Methods A cross⁃sectional study was carried out among 2 754 puerperae who visited the outpatient clinic for 42 days postpartum in the Obstetrics and Gynecology Hospitals in Guangzhou city and Qingyuan city from January to December 2020. A field questionnaire survey was conducted to collect clinical information. On ⁃the ⁃ spot questionnaire survey was used to collect relevant clinical data. Result Among the 2 754 participants，there were 450 with GDM（16.3%），61 with HDP（2.2%），21 with GDM combined with HDP（0.8%）. After controlling maternal age，gravidity and parity，results showed cesarean section delivery was 1.31⁃fold（95%CI：1.05 ~ 1.63），1.87⁃fold（95%CI：1.10 ~ 3.19）and 2.74⁃fold（95%CI：1.11 ~ 6.74），respectively，increased in pregnant women with GDM，HDP and GDM combined with HDP than in those without. Compared with women without GDM or HDP，women with HDP and GDM combined with HDP at a 2.51⁃fold（95%CI：1.17 ~ 5.40）and 3.91⁃fold（OR = 3.91，95%CI：1.30 ~ 11.81）higher risk of premature delivery. Women with GDM combined with HDP increased 8.33⁃fold（95%CI：2.54 ~ 27.23）and 7.77⁃fold（95%CI：1.63 ~ 37.04）risk of low⁃birth⁃weight and neonatal hyperbilirubinemia，respec⁃ tively. Conclusion GDM and HDP comorbidity had a synergistic effect on the risk of maternal cesarean section and perinatal preterm birth，low body weight and hyperbilirubinemia.