Objective To prospectively investigate the characteristics and correlative influential factors of pulmonary hypertension (PHT) in patients on long-term maintenance hemodialysis (MHD). Methods Pulmonary artery systolic pressure (PASP) was assessed by echocardiography according to the guideline from the American Society of Echocardiography in 2010 and PASP more than 35 mm Hg was diagnosed as PHT.Echocardiography and pulse wall velocity (baPWV) was performed in the next day after hemodialysis.Arteriovenous fistula (AVF) flow was evaluated by the ultrasound dilution method.Hemodialysis-related informations and laboratorial parameters were detected in the same period. Results One hundred and eleven MHD patients [male 45,female 66,mean age (57.32±12.49) years old] in our hemodialysis center were included in the study.All of the patients received MHD treatment for more than 6 months with AVF as the vascular access.The patients with any possible diseases causing PHT were excluded.The mean MHD period was (70.51±44.98) months.Twenty-eight patients (25.32％) were diagnosed as PHT with mean PASP (45.68±10.83) mm Hg.Left ventricular diastolic dysfunction was severer in patients with PHT than that in patients without PHT.The prevalence of moderate to severe diastolic dysfunction was statistically higher in PHT group compared to non-PHT group (53.60％ vs 6.02％,P＜0.01).Ejection fraction (EF),fractional shortening of left ventricular diameter in PHT group were also significantly lower than those in non-PHT patients (62.06％±14.90％ vs 69.72％±8.60％,36.46％±10.04％ vs 40.20％±7.86％,P＜0.01).The patients with EF less than 50％ were 21.43％and 3.61％ in PHT and non-PHT group respectively.However,there were no significant differences in age,sex,MHD periods,body mass index (BMI),interval dialysis weight growth,blood pressure before dialysis,hemoglobin,albumin,pre-albumin,serum calcium and phosphorus,iPTH,nPCR,Kt/V,baPWV and AVF flow between the two groups. Conclusions PHT is a common complication of patients on long-term MHD.There is close relationship between PHT and left ventricular insufficiency.PHT is not significantly relevant to mineral metabolic disturbance,AVF flow,hemoglobin,dialysis adequacy and nutrition status.