To understand the behavioral logic and ecological impacts of livestock keeping of migrant households under the background of urbanization in pastoral areas, three villages of Yushu Tibetan Autonomous Prefecture Qinghai Province were selected as the case study sites, and the data were obtained through questionnaires and interviews. The forms and reasons of livestock keeping were presented, the change of livestock population and herd’s perception were evaluated, and influencing factors of livestock keeping were further explored based on the Scott’s safety-first principle of moral peasant. The results show that migrant households kept livestock as an adaptation strategy to urbanization through division of labor, entrusting to kins or employing herders. Households kept livestock mainly for safety need and households with higher income also showed the characteristics of rational peasant. Household with larger family size and non-living causes to migrate were more inclined to keep livestock. Household with higher income had higher probability of keeping livestock and more livestock, while households with more members employed had a lower probability of keeping livestock. This adaptation strategy was restricted by factors such as social relations and economic cost and seems difficult to sustain. Though livestock keeping of migrant households did not increase grazing pressure, the attentions should be paid to the specific form of livestock keeping, the possibility of migrant herders to move back, the change of behavioral logic and the animal husbandry of non-migrant households to achieve the goal of reducing livestock through encouraging herders to migrate to the urban.