Abstract: 【Abstract】　Objective　To investigate the characteristics of Apelin in serum and its relationship to plasma lipid profil of essential hypertension(EH) and EH complicated with diabetes mellitus type 2(T2DM). Methods　34 patients with EH, 35 patients with EH and T2DM(EH+T2DM) and 19 healthy subjects of control group(NC) were selected, to measure the serum level of Apelin in each group by enzyme linked immunosorbent assay(ELISA)and also measure the totel cholesterol(TC)，triglyceride(TG)，high-density lipoprotein(HDL)， low-density lipoprotein(LDL)and fasting plasma glucose(FPG). Results The serum levels of Apelin in the group of EH and EH+T2DM were significantly higher than that in the group of NC(P<0.05)，the serum level of Apelin in the group of EH was significantly lower than that in the group of EH+T2DM (P<0.05).There were positive correlation between the serum apelin and systolic pressure(SP)，diastolic pressure(DP)，mean arterial pressure(MAP)，FPG，body mass index(BMI) and TG，and negative correlation between it and the HDL. Conclusion The serum level of Apelin in the group of EH may be high，and the serum level of Apelin is related with obesity，glucose and lipid metabolism.

Key words: Apelin, hypertension, diabetes mellitus, type 2