Abstract: Objective To study the char acteristics and differences of serum bone alkaline phosphatase(BAP)and ost eocalcin(OC)in tibetan adolescents living on Lhasa and Naqu.Methods 1 458 healthy tibetan adolescents in Lhasa and Naqu aged 12~18 were selected in the study.Their height and the levels of BAP,OC were tested.Results The values of serum BAP、OC reached the peak occurring in Lhasa boys at 13~14 years old and girls at 12 years.The levels of BAP,OC in Naqu were observably lower than those in Lhasa at mostly age(P<0.05).BAP,OC levels in Naqu reached peak approx imately 1 year earlier,which declined with the increase of age after peak.No significant difference was observed for serum BAP,BGP in Lhasa girls after 16 years old and Naqu boys after 16 and Naqu girls after l5(P>0.05).Positive corr elativity was observed between BAP,OC and height.Conclusion Serum BAP,OC in tibetan adolescent in Lhasa and Naqu are closely associated with age and sex,but the levels were lower,the peak was earlier and persistent time of high level was shorter in Naqu than that in Lhasa.The characteristics of BAP and OC maybe one of the reasons of lower height.