Objective This study aims to investigate the influences of body weight on bone mineral content (BMC) and bone mineral density (BMD) of lumbar spines and proximal femur in healthy children and adolescents aged 6-15 years and to compare the differences between BMC and BMD. Methods The BMC and BMD of anteroposterior and supine lateral lumbar spines and proximal femur in 547 healthy children and adolescents from Changsha region were measured by DXA QDR-4500A fan beam bone densitiometry. Results The body weight, body mass index (BMI), BMC and BMD of lumbar spines and proximal femur increased with age in both male and female children and adolescent(P< 0.05 or 0.01). The body weight was more correlated with BMC than with BMD. The BMC adjusted by weight of lumbar spines and proximal femur increased,while the BMD adjusted by weight of them decreased with age. Conclusions It is suggested that BMC is more coincident with the property of bone intensity in terms of mechanics so BMC is a better marker than BMD for the assessment of bone intensity in children and adolescents aged 6-15 years.