Objective To investigate the relation between the skeletal age and the rate of tooth movement. Methods Twenty-three female patients was included in this study.The age for those patients ranged from 12 to 14 years old (mean 13.4).All patients were required the removal of first premolars in both arches.Assessment of the skeletal age was made with a hand radiograph before treatment.Comparatively constant force of 150 grams was used for canine retraction.The rate of canine movement was measured. Results Using comparatively constant force to move canine distally,large individual differences were found in the rate of canine movement.There was no linear correlation between chronological age and the rate of canine retraction.But there was a linear relationship between the skeletal age and the rate of canine retraction.The canines moved distally more slowly followed skeletal age increasing. Conclusion The rate of tooth movement varied among individuals.Skeletal age seems to be a critical factor in regulating rate of tooth movement.