Objective To explore the effect of modified levitating ball breath training on improving quality of pulmonary ventilation function testing in hospitalized children. Methods A total of 755 children undergoing pulmonary function testing were devided into a control group (374 cases) and an experimental group (381 cases) according to hospitalization district. All children were given routine exhalation instruction, while the experimental group was additionally given modified levitating ball breath training, and the effect of exhalation training was judged according to the quality control level of pulmonary ventilation function testing. Results The proportion of level A pulmonary function testing quality in the experimental group was significantly higher than that in the control group (P<0.01). All children in the experimental group could tolerate the exhalation training, 75.59% of whom insisted on the exhalation training every day and 79.20% of whom reached the training times standard per day, and 41.99% of whom reached the training time length standard. Conclusion The modified levitating ball breath training can effectively improve quality of pulmonary ventilation function testing in hospitalized children.