Abstract: AIM To analyze the risk factors of adverse events and the improvement of right atrial size before and after surgery in patients with congenital heart disease with pulmonary arterial hypertension (CHD-PAH). METHODS From June 2014 to June 2016, 79 patients with CHD-PAH underwent surgical repair. There were 25 males and 54 females, 18 to 61 years old. Newly diagnosed, to having a diagnosis PAH and oxygen reactive pulmonary vasculature by right heart catheterization, 13 patients with pulmonary vascular resistance (PVR)<10 Wood units, Qp/Qs≥1.5, SaO2≥95% underwent direct surgical repair, who have better cardiac function. The remaining 66 patients received targeted therapy three months，then had an additional right heart catheterization. RESULTS The early postoperative adverse events included pulmonary crisis in 11 patients, tracheotomy with difficulty in extubation in 4 patients, low cardiac output syndrome occured in 2 patients; and there were 53 patients with postoperative right atrium returned to normal size. The preoperative PVR≥10 Wood units, Qp/Qs, SaO2, systolic pulmonary arterial pressure/systolic blood pressure (SPAP/SBP)>0.75, SPAP, DPAP (P<0.01) were influencing factors in the early postoperative adverse events. Univariate analysis revealed that the higher the SaO2 (OR=0.584, P=0.015), the lower the incidence of adverse events. Preoperative PVR≥10 Wood units, right atrial pressure (RAP)>8 mmHg, shunting direction (P<0.05) were the significantly impacted right atrial enlargement. Univariate analysis revealed RAP>8 mmHg (OR=3.398, P=0.029) was the independent risk factors of right atrial improvement. CONCLUSION The risk factor for postoperative adverse events in CHD-PAH patients was reduction of SaO2, and risk factor for right atrial improvement was RAP>8 mmHg.