OBJECTIVE: To study the development of pulmonary function of healthy children between 1- 48 months.METHODS: A total of 295 healthy children at ages of 1- 48 months were classified into 7 groups according to their age, i.e., 1-2 months, 3- 4 months, 5-7 months, 8-12 months, 13-24 months, 25-36 months, and 37- 48 months. Pediatric pulmonary function laboratory type 2600 (Sensor Medics Corporation USA) was used to detect tidal flow volume curve, which can partially replace the maximum expiratory flow volume curve and reflect airway ventination function. Passive expiratory flow volume technique was used to examine respiratory system static compliance and total airway resistance. Open nitrogen washout method was used to measure functional residual capacity. RESULTS: The values of tidal, peak tidal expiratory flow, and respiratory system static compliance functional residual capacity increased with the increasing age and were significantly different among the 7 groups. However, respiratory rate and total airway resistance decreased with the increased age. The value of each parameter of tidal flow volume curve was stable during 1-48 months.CONCLUSIONS: This study displayed the developmental characteristics of pulmonary function of healthy children at ages of 1-48 months, which is useful to observe the changes of pulmonary function in respiratory diseases.