目的  探讨西部蒙古族4个族群的身体组成成分特点。  方法  采用生物电阻抗分析法测量青海和硕特部361（男性166，女性195）例、新疆察哈尔部443（男性217，女性226）例、新疆土尔扈特部239（男性112，女性127）例、阿拉善和硕特部233（男性89，女性144）例西部蒙古族4个族群18项身体组成成分指标，采用主成分分析探讨中国西部蒙古族身体组成成分的特点。  结果  得出了西部蒙古族4个族群的身体组成成分数据。绝大多数指标性别间差异具有统计学意义，女性躯干、四肢的脂肪率较高，男性肌肉量较大。主成分分析表明，与中国南方族群相比，中国北方族群骨量更大，肌肉更发达，脂肪发育水平更高。在主成分散点图上，中国西部蒙古族与其他族群距离较远，表明西部蒙古族身体组成成分具有独特的特点。  结论 在中国族群中，西部蒙古族骨量大，肌肉发达，体脂率高。 

Objective  To explore the body composition characteristics of four ethnic groups in Western Mongolia.   Methods  Bioelectrical impedance analysis was used on the Western Mongolia four ethnic groups 18 indices of body composition. which include Qinghai Khoshut tribe(166 males, 195 females), Xinjiang Chahar tribe (217 males, 226 females), Xinjiang Torgouts tribe(112 males, 127 females), Alxa Khoshut tribe (89 males, 144 females).Using principal component analysis method  to explore the characteristics of the Mongolian body composition in the west of China.   Results  The body composition data of four ethnic groups were obtained. The gender difference of most indicators was statistically significant. The fat rate of female trunk and limbs was higher, while the muscle mass of male was larger. Principal component analysis showed that compared with the southern ethnic group, the northern ethnic group had larger bone mass, more developed muscles and higher level of fat development. On the principal component scatter plot, the distance between the mongols in Western China and other ethnic groups was relatively far, indicating that the body composition of the mongols in Western China had unique characteristics.   Conclusion  Among the Chinese ethnic groups, the Western Mongolians have large bone mass, well developed muscles and high body fat.