Objective: To explore the characteristics and prognostic value of pulmonary hemodynamics in patients with acute coronary syndrome (ACS). Methods: From a prospective multicenter registry study of pulmonary hypertension due to left heart disease, consecutive ACS patients who underwent coronary angiography in combination with left and right heart catheterization during hospitalization between January 2013 and November 2016 were involved. The primary endpoint was all-cause mortality. The prognostic variables identified by the Lasso analysis were included in the Global Registry of Acute Coronary Events (GRACE) score. Model performance was evaluated before and after the addition of hemodynamic parameters. Results: A total of 251 patients were enrolled, with age of (63.7±11.5) years. A total of 198 males (78.9%) and 53 females (21.1%) were recruited, and the median follow-up time was 34.7 months. Right heart catheterization-assessed mean pulmonary arterial pressure (mPAP), systolic pulmonary arterial pressure (sPAP) and diastolic pressure gradient (DPG) were found to be significant predictors for survival in ACS. Adjusted for age and sex, the adjusted HR (95%CI) of mPAP, sPAP and DPG were 1.068 (1.015-1.123), 1.033 (1.002-1.065) and 1.094 (1.008-1.187), respectively (P<0.05). Applied to the present cohort of 251 patients, the median of the GRACE score was 123 points, with a C-index of 0.703 (95%CI: 0.615-0.791) for predicting mortality. After the addition of mPAP or DPG to the GRACE score, the C-index increased to 0.715 (95%CI: 0.629-0.801) or 0.711 (95%CI: 0.625-0.797), respectively. When comparing two models before and after the addition of mPAP or DPG, the integrated discriminatory index (IDI) was 4.3% (95%CI: 0.2%-13.5%, P=0.030) and 3.0% (95%CI: 0.2%-11.1%, P=0.020), respectively. Conclusion: Pulmonary hemodynamics can be predictive for survival in ACS patients, providing incremental prognostic value to risk assessment in ACS.