Objective: In the present study, we aimed to investigate the effect of pulmonary arterial perfusion (PAP) with Histidine–tryptophan–ketoglutarate (HTK) on lung protection in infants with congenital heart disease (CHD) and pulmonary arterial hypertension (PAH) after cardiopulmonary bypass (CPB).Methods: Fifty infant patients with CHD and PAH at our hospital from January, 2016 to February, 2017 were randomly divided into control group and HTK group. The levels of interleukin-6 (IL-6), malondialdehyde (MDA), and endothelin-1 (ET-1) in serum were detected using ELISA Kit. Oxygen index (OI) and respiratory index (RI) were calculated at each time point. The time of postoperative mechanical ventilation and ICU stay was counted, and the right lower lung tissues in patients were taken for pathological examination.Results: Compared with preanesthesia, the levels of IL-6, MDA, and ET-1 in the two groups were significantly increased after CPB, and their levels in HTK group were significantly lower than that in control group. Moreover, OI in control group decreased markedly and RI in control group increased significantly after CPB. Compared with control group, the postoperative mechanical ventilation time, postoperative ICU stay, and total hospital stay in HTK group were markedly short. In addition, inflammatory cells infiltration decreased and pulmonary interstitial showed mild edema in HTK group.Conclusion: PAP with HTK could effectively reduce CPB-induced lung injury and improve lung function.