Although numerous studies concerned about the livelihood vulnerability to climate change at district or community level,few researches on how to precisely identify the vulnerable population have been done. A household-level assessment of livelihood vulnerability contributes to a deeper understanding of the characteristics of vulnerable population,enlightening the policymaker to develop climate change adaptation strategies and poverty alleviation policies for farmers and herders. In this study,188 households were investigated along the Yarlung Zangbo River,the Nyangqu River and the Lhasa River Region (the YNL river region) in the Tibetan Plateau. Followed by a framework of sustainable livelihood analysis and an approach of evaluation onrisk-livelihood assetadaptive capacity,a household-level livelihood vulnerability indicator system was introduced and accordingly the sampled households were classified into two categories (i. e., the highly and the lowly vulnerable households) using K-means clustering. The results showed that: (1) The highly vulnerable households accounted for 43.09% of all involved households,which featured in a higher level of risk,but a lower level of livelihood assets and adaptive capacity as compared with those of the lowly vulnerable households. (2) Compared to the lowly vulnerable households,the distinguishing feature of the highly vulnerable households were those,such as highly subjected to natural resources,more susceptible to extreme climate disasters,poor livelihood diversification,and insufficient government subsidies. The study suggests that the government should actively take actions to control natural disasters,to improve educational level and to promote livelihood diversification,which would help farmers and herders improve their adaptive capacity and reduce livelihood vulnerability.