Objective To analyze the relationship of P-wave index (PWI) with mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) in patients with pulmonary hypertension. Methods 37 patients with pulmonary hypertension (study group) and 33 healthy subjects with physical examination (control group) in The Second Affiliated Hospital of Bengbu Medical University, from January 2020 to January 2024 were selected as the study samples. PWI, mPAP and PVR were obtained by electrocardiogram machine and ultrasound cardiotachograph in all patients. The differences in PWI, mPAP and PVR were compared between study group and control group, and the correlation between PWI and mPAP and PVR in patients with pulmonary hypertension was analyzed. After 3 months of follow-up, the patients with pulmonary hypertension were divided into poor prognosis group and good prognosis group according to follow-up results, and the differences in PWI, mPAP and PVR were compared. Receiver operating characteristic (ROC) curve was used to evaluate the application value of PWI, mPAP and PVR in predicting the poor prognosis of patients with pulmonary hypertension. Results The P wave duration, PR interval, P wave dispersion, mPAP and PVR in study group were all higher than those in control group while the PTFV1 was lower than that in control group (P<0.05). P wave duration, PR interval and P wave dispersion in patients with pulmonary hypertension were positively correlated with mPAP and PVR, while PTFV1 was negatively correlated with mPAP and PVR (P<0.05). After 3 months of follow- up, 8 patients had poor prognosis. The P wave duration, PR interval, P wave dispersion, mPAP and PVR were higher in poor prognosis group than those in good prognosis group while PTFV1 was lower (P<0.05). The AUC values of P wave duration, PTFV1, mPAP and PVR were 0.828, 0.778, 0.806 and 0.761 respectively. The combination of the four items had the highest value on predicting poor prognosis (P<0.05), and the sensitivity and specificity were 87.50% and 44.83% respectively. Conclusion There is a close relationship between PWI and mPAP, PVR in patients with pulmonary hypertension. Pulmonary hypertension patients with high levels of P wave duration, mPAP and PVR and low level of PTFV1 are high-risk groups with poor prognosis. It is necessary to take clinical treatment measures as soon as possible and strengthen the follow-up management.