The Gutianshan National Nature Reserve (GNR) is home to  a major population of black muntjac (Muntiancus cirnifrons), an endemic species of China that is faced with the threat of habitat loss and fragmentation. We used MAXENT modeling to assess the habitat suitability of black muntjac during different seasons. Data from camera-trapping collected during 2014-2017 and 12 environmental variables for GNR is used in the analysis. The results show that the habitat suitability of black muntjac in GNR changed with seasons. Distance to broad-leaved forest and elevation were major factors that influenced the habitat selection of black muntjac. The area of suitable habitats for black muntjac varied by were 2086.38 ha in spring, 2608.74 ha in summer, 2502.27 ha in autumn, and 1746.27 ha in winter, which accounted for 25.74%, 32.18%, 30.87%, and 21.54% of the GNR area in spring, summer, autumn, and winter, respectively. Most of the suitable habitats for black muntjac were in the core zone and along the northern edges of GNR. We recommended strengthening the protection and restoration of the natural vegetation in the core zone and northern edges, reducing human activities for the protection of black muntjac in GNR.