Abstract: Da-ba Mountain is the main distribution area of the rare and endangered plant Thuja sutchuenensis in China. In this study,principal component analysis and random forest model were used to screen the environmental factors that affected the growth of Thuja sutchuenensis, and then the factors with higher contribution rate were imported into the MAXENT model to evaluate and analyze the factors affecting the habitat suitability of Thuja sutchuenensis in the study area. Further, the ecological security evaluation index system was used to evaluate the ecological environment of the study area, and the potential distribution regional level map was obtained by superposition analysis of the two. The results showed that the ecological security index of the study area was relatively high, and the ecological security was generally good, and the habitat quality of Thuja sutchuenensis was excellent, and water vapor pressure in July, average temperature in the warmest quarter and average temperature in the coldest quarter were the top three factors affecting the habitat of Thuja sutchuenensis. The potential distribution area of Thuja sutchuenensis was mainly in the middle and south of the study area. The suitable habitat conditions of Thuja sutchuenensis were as follows: the average temperature in the warmest season was 12～14℃, the average temperature in the coldest season was-2～0℃, and the water vapor pressure range in Julywas1.7～1.9 kPa. It is suggested to strengthen the protection and restoration of the core area and the southern area of Da-ba Mountain, as well as the supervision and management of human disturbance activities in the reserve.