Objective To investigate and analyze the level of homocysteine(Hcy)in Tibet and to analyze the differences of Hcy level in different altitude regions,genders and ages,and thus to provide the prevalence profile of hyperhomocysteine and the differences in relevant tests between HHcy(hyperhomocysteinemia)and non-HHcy pop-ulations.Methods Totally 1 615(male n＝585)subjects were selected from Ngari,Lhasa,Shigatse and Nyingchi plat-eau areas of Tibet by stratified cluster sampling.Serum Hcy level was analyzed and the difference of Hcy level in pop-ulations located at different altitude plateau areas,gender groups were found.The prevalence of hyperhomocysteine and related test were analyzed.Kruskal Wallis test was used to compare Hcy levels in different altitudes,genders and age groups,and Pearson Chi-square test was used to compare HHcy prevalence.Variance analysis was used for the differences of different test indicators between non-HHcy and HHcy populations.Results The level of Hcy in differ-ent regions and different genders were statistically significant,which was higher in males than that in females,and higher in Lhasa and Shigatse than in Nyingchi and Ngari.There was difference in serum HHcy prevalence among dif-ferent genders,regions and age groups.Males showed a higher level than females,people from Lhasa and Shigatse showed a higher level than those from Nyingchi and Ngari.Conclusions The incidence of hyperhomocysteinemia in Tibet is statistically significant in different areas,different genders and different age groups.So this study provides a scientific basis for the rational use of Hcy as an indicator in clinical practice of prevention and treatment of related diseases in plateau areas.