Objectives To analyze the changes of serum complement C1q level in patients with metabolic syndrome (MS) and investigate whether it is associated with lipid metabolism and glycometabolism. Methods In a cross-sectional study, the subjects were selected as the patients and healthy people who went to the second xiangya hospital of central south university from July 2017 to June 2018. A total of 152 MS patients were enrolled and another 90 healthy subjects were enrolled as control group. Anthropometry parameters such as body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP) were measured. Serum concentrations of C1q and other biochemical indexes including blood glucose (GLU), triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were measured in all groups. The correlations between C1q and these parameters were analyzed by spearman's rho test and the clinical value of C1q in predicting MS was further evaluated by stepwise multiple linear regression analysis. Results MS group had higher serum C1q levels (244.34±62.66) mg/L compared with the control group (202.37±35.92) mg/L (t=-6.250, P=0.000). C1q levels (244.34±62.66) mg/L were positively associated with TG levels [2.34(1.89, 3.62)] mmol/L (r=0.245, P=0.001), TC levels (4.91±1.26) mmol/L (r=0.398, P=0.000), LDL-C levels (3.23±1.03) mmol/L (r=0.325, P=0.000) in MS group, While C1q levels (258.92±69.59)mg/L were positively associated with SBP (144.76 ± 22.94) mmHg (r=0.388, P=0.018), TG levels [2.65(1.87, 3.82)] mmol / L (r=0.482, P=0.003), TC levels (5.18±1.31) mmol/L (r=0.529,P=0.001) in MS patients with obesity. The stepwise multiple regression analysis showed that TG levels were independently correlated with serum C1q levels both in MS patients (β=0.302, P=0.000) and in MS patients with obesity (β=0.653, P=0.000) after adjusting for age, gender and other biochemical markers. Conclusions MS patients had higher C1q levels than healthy subjects and serum C1q levels were closely positive related to harmful lipid profiles. Serum TG level was an independent influencing factor of serum C1q in MS patients.