OBJECTIVE: The reference values of pulmonary function for healthy schoolchildren were established between late 1980's and early 1990's. Whether the improvement of life quality influences the pulmonary function values of schoolchildren remains unknown. Moreover, the pulmonary function values of children from different regions might be different. This study aimed to investigate the mean values of pulmonary function parameters in healthy children aged 6 to 12 years in Guangzhou. METHODS: Spirolite TM 303 pulmonary function test spirometer was used to measure the mean values of pulmonary function parameters, including forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV_1), peak expiratory flow (PEF) and forced expiratory flow during middle half of FVC (FEF_ 25%-75%), in 280 healthy schoolchildren between 6 and 12 years old of both sexes from a primary school of Guangzhou. The subjects selected by random sampling were assigned into 7 groups according age (n=40 each), 1 year as a group separation. Their weights and heights were measured. RESULTS: In 139 boys the mean weight and height were 32.93±7.39 kg and 135.05±13.42 cm, respectively. The mean FVC was 3.40±0.96 L, FEV_1 3.03±0.87 L, PEF 6.42±2.32 L and FEF_ 25%-75% 3.58±1.32 L . In 141 girls the mean weight and height were 33.06±6.85 kg and 135.66±12.62 cm, respectively. The mean FVC was 3.22±1.07 L, FEV_1 2.88±0.93 L, PEF 5.84±2.17 L and FEF_ 25%-75% 3.59±1.28 L. Monovariable analysis showed that all the four parameters were positively related to height and weight but multivariable regression analysis did not demonstrate a correlation between the four parameters and weight. Monovariable analysis showed that PEF was related to gender but FVC, FEV_1 and FEF_ 25%-75%, were irrelevant. However multivariable regression analysis showed that FVC and FEV_1 were also correlated to gender. Either the monovariable analysis or the multivariable regression analysis demonstrated that all the four parameters were positively related to age. CONCLUSIONS: This study reported a reference range of the pulmonary function values for healthy schoolchildren aged 6 to 12 years in Guangzhou. Age, height, weight and gender may be related to the pulmonary function values. Among them, age and height are more important impact factors.