Objective:To examine the effect of short-term regular aerobic exercise on physical fitness of children with pulmonary with atresia ventricular septal defect after radical biventricular treatment.Methods:This was a prospective self pre-and post-control observation study. The subjects performed regular aerobic exercise for 10 days according to the exercise prescription. Body composition measurement and cardiopulmonary exercise test[lung ventilation function, maximum oxygen uptake(VO 2max), maximum oxygen pulse(O 2/HR max), ventilation oxygen uptake efficiency(OUES), exercise load time], 6 min walking distance(6MWD), sports psychometric test, motor function screening test and fitness test, were collected. The changes of test parameters and scale scoring before and after exercise were analyzed and compared. Results:A total of 7 children with PA/VSD after biventricular surgery were enrolled. The age ranged 8.2-16.2 years old, and there were 2 males and 5 females. VO 2max[(1 196.71±395.31)ml/min vs.(1 297.43±425.73)ml/min, P=0.031], O 2/HRmax[(82.43±7.53)ml/beat vs.(91.57±6.95)ml/beat, P<0.001]increased after exercise. The exercise load time was significantly increased compared with that before intervention[(476.43±35.73)s vs.(531.43±45.76)s, P=0.002]. Resting heart rate before exercise( P=0.013) and peak respiration exchange ratio(PeakRER, P=0.021) were significantly lower. Body composition tests suggest weight, intracellular water, protein and muscle content of lower limb were higher( P<0.05). The motor function score was higher than before( P=0.015); the score of sports fear was lower than before( P=0.009). There was no significant difference in lung capacity and 6-minute walking distance before and after exercise( P>0.05). There were no cardiovascular events during the study period. Conclusion:Short-term regular aerobic exercise for children with PA/VSD after biventricular surgery can improve exercise tolerance, increase lower limb muscle content, improve exercise fear and exercise function, and has good safety and feasibility.