ABSTRACT Objective Echocardiography was used to evaluate the relationship between pulmonary artery stiffness (PAS) and ventricular remodeling in patients with obstructive sleep apnea syndrome (OSAS). Methods A total of one hundred and thirty-seven patients with OSAS diagnosed by polysomnography (PSG) with apnea hypopnea index (AHI)≥5/h were enrolled. Blood pressure and general clinical characteristics were collected and echocardiography was performed next morning. On the basis of left ventricular mass index (LVMI) and relative wall thickness (RWT), patients were divided into 4 groups: normal geometry (NG), concentric remodeling (CR), eccentric hypertrophy (EH), concentric hypertrophy (CH). At the same time, 35 healthy volunteers were selected as the control group. Parameters related to left ventricle, right ventricle and PAS were collected, and the differences between groups were compared. Correlation analysis was conducted for PAS and right ventricular parameters, and regression analysis was conducted for the risk factors related with PAS. Results ①Compared with control group, PAS increased in each OSAS group (all P<0.05). Compared with NG group, PAS increased in CR and EH group (all P<0.05). Compared with NG, CR and EH group, PAS increased in CH group (all P<0.05). ② Correlation analysis between PAS and right ventricular parameters in patients with OSAS showed that PAS was negatively correlated with Et/At (r=-0.376, P<0.05), and positively correlated with right ventricular diameter(r=0.363, P<0.05), Tei index (r=0.366, P<0.05) and mPAP (r=0.631, P<0.05). ③Correlation analysis of PAS with clinical, sleep and echocardiographic parameters showed that PAS was positively correlated with age (r=0.154, P<0.05), body?mass?index?(r=0.166, P<0.05), systolic blood pressure (r=0.253, P<0.05), diastolic blood pressure (r=0.153, P<0.05), AHI (r=0.336, P<0.05), LVMI (r=0.276, P<0.05), RWT (r=0.286, P<0.05), left ventricular geometry (r=0.433, P<0.05), and positively correlated with Lowest Sa02 (r=-0.158, P<0.05). ④Multiple linear regression analysis showed that PAS was independently correlated with age (t=2.426, P<0.05), AHI (t=2.477, P<0.05), left ventricular geometry (CR: t=2.422; EH: t=2.334; CH: t=3.101, all P<0.05). Conclusions The changes of PAS in OSAS patients with different left ventricular geometry are different, PAS is independently related to abnormal left ventricular geometry, suggesting that PAS is related to the process of ventricular remodeling.