Objective: To explore the correlation between serum interleukin-32 (IL-32) level and the presence and severity of pulmonary arterial hypertension (PAH) associated with congenital heart disease (CHD). Methods: Eighty-five CHD patients were enrolled in the experimental group, and these patients were divided into the non-PAH group ( PAPm ≤slant 20 mmHg ), grey area group ( 20 mmHg ＜ PAPm ＜25 mmHg ), mild group (25 mmHg ≤slant PAPm ＜35 mmHg ), and moderate-severe group ( PAPm ≥slant 35 mmHg ) by mean pulmonary artery pressure ( PAPm) measured using right heart catheterization; the control group consisted of 30 healthy adults. Enzyme-linked immunosorbent assay (ELISA) was used to measure serum IL-32 level in various groups, and chemiluminescent microparticle immunoassay (CMIA) was used to measure the plasma B-type natriuretic peptide (BNP) level in the experimental group. Results: Serum IL-32 levels in the moderate-severe, mild, and grey area groups were significantly higher than those in the non-PAH and control groups. The serum IL-32 level in CHD (Qp/Qs ≥slant 1.5 ) patients was significantly higher than that in CHD (Qp/Qs ＜1.5 ) patients. The serum IL-32 level was positively correlated with \operatorname{PAPm}(r=0.377, P＜0.05), pulmonary artery systolic pressure (r=0.286, P＜0.05), and Q p / Qs (r=0.266, P＜0.05). Receiver operating characteristic (ROC) curve analysis found that the performance of IL-32 in the diagnosis of PAH (PAPm ＞20 mmHg ) was non-inferior to BNP, and diagnosis using the combined IL-32 and BNP had higher sensitivity, positive predictive value, and negative predictive value. Conclusion: Serum IL-32 may be a biomarker for PAH associated with CHD.