Objective To evaluate apelin level in patients with obesity and different glucose tolerances, investigate relevance of apelin with body mass index(BMI), blood lipid and blood glucose. Methods According to different glucose results of oral glucose tolerance test, 120 subjects were divided into three groups: normal glucose tolerance(NGT),impaired glucose tolerance(IGT) and type 2 diabetes(T2DM). All of the subjects were also divided into obese and non-obese subgroups based on their BMI(≥25kg/m~2 or ＜25kg/m~2 ). Plasma apelin levels were compared among groups of NGT, IGT and T2DM. Fasting plasma glucose(FPG)and 2h postprandial plasma glucose (2hPG) after OGTT, lipid profile and BMI were measured. Results Both fasting and 2h postprandial plasma apelin had significant differences in these groups (P<0.05,or P<0.01). The overweight and obese subgroups in the IGT group and diabetes group had higher apelin levels than their counterpart subgroups in the NGT group. BMI, FPO, systolic blood pressure(SBP) were independent influencing factors for apelin (P<0.05 ,or P<0.01). Conclusions Plasma apelin level is related to obesity and type 2 diabetes.