Abstract: Objective To investigate effect of asthma on bone development in children. Methods A total of 80 children with mild or moderate bronchial asthma diagnosed in pediatric asthma outpatient department of Affiliated Hospital of Qingdao University were selected as the research objects, among whom 40 children diagnosed as mild bronchial asthma children were selected as mild asthma group, another 40 moderate bronchial asthma were selected as moderate asthma group. These children were treated with low dose of glucocorticoid after diagnosis. At the same time, thirty healthy children with physical examinations were selected as control group. Bone mineral density(BMD)and serum 1, 25-dihydroxyvitamin D₃［1, 25-(OH)₂D₃］ of three groups were measured. Results BMD values of mild asthma group and moderate asthma group were lower than those of the control group, and the difference was statistically significant(P<0.05). The serum 1, 25-(OH)₂D₃ level in the moderate asthma group was significantly lower than that in the control group(P<0.05). The serum 1, 25-(OH)₂D₃ level in the mild asthma group was slightly lower than that in the control group, but no difference was found(P>0.05). Conclusion Asthma without regular treatment can delay the bone development in children, the severer degree of asthma is, the more effect it will be.