Abstract： Objective To explore the characteristics of maternal glucose and lipid metabolism in twin pregnancies complicated by gestational diabetes mellitus (GDM). Methods The clinical features of twin and singleton pregnancies complicated by GDM, which delivered in Peking University First Hospital from January 1st, 2012 to December 31st, 2017 were retrospectively analyzed. A total of 286 twin pregnancies with GDM (GDM-T group) were collected, and 572 singleton pregnancies complicated by GDM (GDM-S group) which were matched by delivery time in a ratio of 1∶2 among all singleton pregnancies with GDM. The characteristics of maternal glucolipid metabolism in the second trimesters of pregnancy was compared between two groups. Results (1) Compared with GDM-S group, the maternal delivery age were lower [(32±4), (33±4) years] and prepregnancy body mass index (BMI) were higher [(24±4), (23±4) kg/m2] in GDM-T group, the differences were statistically significant (all P<0.05). The incidence of chronic hypertension was found no significant difference (P=0.581). (2) The 3 points of glucose values in 75 g oral glucose tolerance test (OGTT) and OGTT-area under curve (AUC) had no significant difference between GDM-T and GDM-S group.When compared with GDM-S group, the maternal glycosylated hemoglobin levels [(5.41±0.35)%, (5.32±0.28)%],the insulin resistance index (4.07±0.77, 2.63±1.50) and the proportion of insulin use (7.7%, 4.4%) were all significantly higher in GDM-T group (all P<0.05). The values of triglyceride [(3.4 ± 1.4), (2.6 ± 1.2) mmol/L], total cholesterol [(6.3 ± 1.1), (6.0 ± 1.0) mmol/L], low density lipoprotein cholesterol [(3.3 ± 0.9), (3.1 ± 0.8) mmol/L] were significantly higher and values of high density lipoprotein cholesterol [(1.7±0.4), (2.0±0.5) mmol/L] were significantly lower in GDM-T group than GDM-S group (all P<0.05). (3) There was no significant difference in the incidence of gestational hypertension between the two groups (P>0.05). When compared with GDM-S group, the incidences of preeclampsia and small for gestational age were both significantly higher (13.3% vs 2.4%; 28.7% vs 1.7%) and the incidence of large for gestational age was significantly lower in GDM-T group (4.5% vs 15.2%; all P<0.05). Conclusions The insulin resistance is aggravated in twin pregnancies and the characteristics of lipid metabolism are different between singleton and twin pregnant women complicated by GDM, and there are more complications in twin GDM pregnancies.