To explore the effects of pre-pregnancy body mass index (BMI), weight gain and blood lipid level during pregnancy on pregnancy outcome in patients with and without gestational diabetes mellitus(GDM). A total of 12 650 singleton pregnant women without history of hypertension and diabetes who were admitted at Women's Hospital, Zhejiang University School of Medicine for delivery from January 2018 to April 2019 were enrolled in the study. There were 2381 cases complicated with gestational diabetes (GDM group) and 10 269 cases without GDM (non-GDM group). The pre-pregnancy BMI and weight gain during pregnancy were documented in two groups. The factors related to perinatal outcome were analyzed. In both GDM and non-GDM pregnant women, pre-pregnancy overweight and excessive weight gain during pregnancy were independent factors of large for gestational age infant (LGA), small for gestational age infant (SGA) and first cesarean section (<0.01 or <0.05). Excessive weight gain during pregnancy was also an independent risk factor of preeclampsia (<0.05). Triglyceride levels in the second trimester were independently associated with multiple adverse pregnancy outcomes, such as LGA, preeclampsia, initial cesarean delivery, premature delivery. Controlling excessive or insufficient weight gain during pregnancy can significantly reduce the incidence of LGA and SGA. And controlling BMI before pregnancy can effectively reduce the incidence of LGA, preeclampsia and the first cesarean section. For non-GDM pregnant women, abnormal blood lipid levels in the second trimester may be closely related to multiple adverse pregnancy outcomes, and active dietary guidance or treatment is also required.