To cope with periodic fluctuations of food resources and environmental stress, it is a common strategy of ungulates by adjusting their time allocation and space use accordingly. In order to investigate alpine ungulates' responses and strategies to these fluctuations, we deployed 29 camera-traps in the habitat of Bharal (Pseudois nayaur), in Wanglang National Nature Reserve, Sichuan Province, from June 2018 to August 2019. We analyzed the spatio-temporal dynamic of Bharal's circadian activities by using Wilcoxon rank sum test in R 3.5.3. According to habitat selection theory and pertinent research, we predicted that Bharal would represent different behavior patterns at the circadian rhythm in facing varied space and time. The results showed that the behavior of Bharal was generally consistent with our predictions. In the first place, during summer daytime and winter night, Bharal was more active in forest edge (summer daytime: 43.64±3.39; winter night: 10.00±0.26) and forest interior (summer daytime: 34.21±3.21, P=0.065; winter night: 8.40±0.64, P=0.026), a possible response to the stress of extreme temperatures in the open meadows. In the second place, during the winter with limited food availability, the night activity intensity of Bharal was significantly higher than that in other seasons (winter: 23.00±0.73; spring: 2.00±0.39; summer: 4.80±1.36; autumn: 15.00±1.31). While in the daytime, more activities were observed in meadow (forest edge: 31.79±3.54, meadow: 22.79±3.16; P=0.081). Different from our expectations, we found Bharal was most active within forest edge (10.00±0.26), than forest interior (8.40±0.64, P=0.026) during winter night. Facing severe environment conditions (low temperature and scarce food), Bharal need to invest more time in foraging and feeding to maintain their energy balance. As a consequence, we believe Bharal chose space close to both food and shelter during winter night when food shortage incompatible, which is the most likely explanation for their behavior pattern during winter night. With the rapid changes of global climate during the past decades, the alpine ecosystems have been seriously threatened. Therefore, we suggest government agencies, societies and researchers pay more attentions to the survival condition of alpine fauna and flora and the stability of the ecosystems. Thereby, there's no doubt about that further researches will provide us increasing knowledge to understand and evaluate the impacts of climate changes on biodiversity.