Objective  To reveal the characteristics of Tibetan human body composition in Gannan.  Methods  The body composition of 410 Tibetan adults (221 males and 189 females) in Gannan was measured by bioelectrical impedance method. The data were processed by SPSS 20.0 statistical software.  Results  Related analysis results showed that the total body muscle mass, estimated fat level and trunk muscle mass of the male decreased with age, while the percent body water, visceral fat level and percent trunk fat increased with age. The stature and left lower limb muscle mass of the female decreased with age, while body weight, percent body fat, body mass index, visceral fat level, percent right upper limb fat, right upper limb muscle mass, percent left upper limb, left upper limb muscle mass, percent right lower limb fat, percent left lower limb fat, left lower limb muscle mass and percent trunk fat increased with age. Analysis of single factor variance showed that there were statistically significant differences in the four indexes of male percent body water, visceral fat level, percent trunk fat and trunk muscle mass, while there were no statistically significant differences in the other 14 indexes among age groups. Females weight, stature, percent body fat, total body muscle mass, estimated fat level, body mass index, visceral fat level, percent right upper limb fat, right upper limb muscle mass, percent left upper limb fat, left upper limb muscle mass, percent right lower limb fat, percent left lower limb fat, left lower limb muscle mass, percent trunk fat, trunk muscle mass 16 index values were statistically significant differences between age groups, the remaining two index values were not statistically significant differences between age groups. The results of u test showed that the body weight, total body muscle mass, estimated fat level, percent body water, limb muscle mass and trunk muscle mass of males were higher than those of females, and percent body fat, limb fat rate, visceral fat rate and trunk fat rate of females were higher than those of males. According to the body mass index, Gannan Tibetan male and female were overweight; according to the percent body fat, Gannan Tibetan males were nonobesity and females were obesity.  Conclusion The body mass index and overall fat content of Tibetan males and females in Gannan are relatively high among the 13 ethnic groups.