Objective To analyze the pulmonary function of students in Grade three of middle school in Jiujiang, in order to provide basis for health education to students. Methods A total of 1 240 students in Grade three of middle school who took physical examination in Maternal and Child Health Care Hospital of Jiujiang from June 2015 to June 2017 were selected into this study.Pulmonary function including vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow rate forced expiratory flow (PEF), forced expiratory flow 25 (FEF25), forced expiratory flow 50(FEF50), forced expiratory flow 75(FEF75) and maximal mid-expiratory flow (MMEF) were assessed and compared among different year, age, gender and body mass index(BMI) groups. Results Pulmonary function of students decreased from 2015 to 2017(P<0.05).Pulmonary function increased with the increase of age (P<0.05).Male students generally had higher level of lung function than female ones (P<0.05).In terms of BMI, pulmonary function was higher in group of 18.5~24.9 kg/m² than that in groups of BMI under 18.5 kg/m² and over 24.9 kg/m² (both P<0.05).The FVC, FEV1 and FEF75 of the group with BMI under 18.5 kg/m² were higher than those of group with BMI over 24.9 kg/m², while other lung function parameters between the two groups had no significant differences(P<0.05). Conclusions Pulmonary function of students tends to decrease year over year.Children who are older, male have higher pulmonary function.While pulmonary function of the overweight or underweight students is lower than that of the normal ones.Therefore, students are suggested to strengthen their physical activities in order to improve their pulmonary function.