Abstract: Objective To compare parathyroid hormone（PTH）level in patients with primary aldosteronism（PA）and essential hypertension（EH）,and to explore the relationship between PTH,aldosterone level and left ventricular hypertrophy. Methods A total of 110 cases with PA and 110 cases with EH individually matched 1∶1 by gender,age,blood pressure and duration of hypertension were recruited from in-hospital patients who were hospitalized because of suspicion of secondary hypertension. The differences in electrolytes,PTH and left ventricular structure were compared between PA and EH patients. Results Serum calcium （2.22±0.16）vs（2.29±0.10）mmol/L,phosphorus（1.00±0.20）vs（1.13±0.20）mmol/Land potassium （3.2±0.5）vs（4.0±1.5）mmol/Lwere lower in PA group than those in EH group.PTH level（71.94±33.92）vs（43.53±19.94）ng/L,P＜0.01and serum sodium （142.3±2.5）vs（140.4±3.0）mmol/L,P＜0.01were elevated in PA patients than EH group. Linear regression analysis showed that aldosterone was positively related to PTH in PA patients（β=0.311,P＜0.05）.Compared to EH group,the left ventricular mass index（LVMI）in PA group was higher201.2（162.4-251.4）vs155.5（131.4-176.1）g/m~2,P＜0.01.Divided the PA group into two subgroups according to the PTH level,the LVMI was elevated in high PTH subgroup than normal subgroup 252.4（240.5-328.9）vs 188.0（145.2-225.5）g/m~2,P＜0.05. Multiple linear regression analysis showed that phosphorus and PTH were influencing factors of LVMI（β=-0.264,0.607,P＜0.05）. In all subjects,admission systolic blood pressure,aldosterone,PTH,serum calcium,waist-hip ratio were influencing factors of LVMI（β=0.292,0.244,0.416,0.241,0.209,P＜0.05）. Conclusion PTH level is higher in PA patients than EH patients,which may contribute to left ventricular hypertrophy combined with aldosterone.