Abstract: Mergus squamatus is an East-Asian endemic and national first-class protected wild animal in China. Quantifying its current habitat distribution in Sichuan Province can provide the baseline data required for evidence-based conservation planning. Through field investigation and database of China Bird Watching Center, 327 occurrence records of M. squamatus in Sichuan Province were obtained, and 91 distribution sites were selected. Combined with 25 environmental factors, the optimal distribution area of M. squamatus in Sichuan Province were predicted by using MaxEnt model with optimized parameters, and the key environmental factors affecting its wintering suitable habitat were analyzed. The results showed that the most suitable distribution area of M. squamatus were mainly located in Sichuan Basin and the mountainous areas of southwest Sichuan, and its main habitat wetland type was riverine wetland, which was mainly located in the water system above the third level of the Yangtze River, including the Yangtze River, Tuojiang River, Minjinag River, Fujiang River, Jialingjiang River, Qujiang River, Qingyijiang River, Anning River and Dadu River. The main environmental factors affecting its wintering habitat selection were land-cover type (Lc, 28.6%), elevation (27.2%), human influence index (HII, 22.4%) and the warmest season precipitation (bio18, 7.5%), and the cumulative contribution rate reached 85.7%. Based on the above results, the following protection suggestions were put forward: (1) Increasing the number of protected areas to increase the protection coverage of key habitats of M. squamatus; (2) Expanding the protection scope of planned protected area and upgrading the protection level; (3) Establishing a long-term monitoring scheme, implementing science-based patrols, and launching community outreach programmes to raise local awareness and reduce anthropogenic disturbance.