Human activities are widely recognized as one of the foremost factors posing a significant threat to biodiversity in the world today. More and more "refugee species" have been restricted to sub-optimal habitats due to the disturbance of human activities. Taking the critically endangered snub-nosed monkey, which faces severe threats in China, as a case study, this research employed the MaxEnt model to predict its historical and current habitats based on the data of topographic variables, human activity variables, climate variables, and distribution data from both past (before the 20th century) and present (from the 20th century to the present day) periods. The findings demonstrate that the human activities have resulted in the loss of 921,756 square kilometers of suitable habitat for the snub-nosed monkey in the eastern part of China since ancient times. Within the retain suitable range, the quality of habitats has declined, while the new suitable habitats had become fragmented and dispersed. Remarkably, the snub-nosed monkey has re-adapted to the sub-suitable or even unsuitable habitats in the historical period. The study further reveals that the snub-nosed monkey's adaptability to climate variables has undergone relatively minor changes compared to its adaptability to topographic variables. Compared with the time when it was free to choose suitable habitats, the altitude and the relief amplitude of the habitat in the current period are higher, the suitable range of the coldest month's lowest temperature and the temperature annual range is narrower. The snub-nosed monkey has enhanced its adaptability to various environmental variables. At the same time, it has concurrently exhibited heightened sensitivity to environmental changes and encountered escalating risks, including increased population isolation. Consequently, the snub-nosed monkey is no longer able to occupy the optimal ecological niche. To mitigate these challenges, it is recommended to pay attention to the intensity of human activities in the vicinity of existing suitable habitats, to minimize competition with the snub-nosed monkey for space or resources, and to enhance the protection of this species.