Water conservation function is the dominant function of ecological system services in the hilly region of Loess Plateau, and plays important roles in the sustainable development of ecological and social economy in this region. This study took Anding District in Dingxi City as an example to evaluate the water conservation function and its spatial distribution in 2017 by using InVEST model, and then this study calculated the cold and hot spots and presented spatial distribution pattern of the importance degree of water conservation function with spatially statistical methods. This study showed that the water annual conservation amount ranged from 0 to 364.541 mm per grid unit. The average annual water conservation amount in the watershed was 36.37 m³/hm², in which the average annual water conservation amount in the Xi River Basin was the highest with 54.64 m³/hm².The total water conservation capacity of the whole watershed was 11900×104 m³, and gradually decreased from the southwest areas to the northeast areas in the whole study region. This study also found that the hot spot region of water conservation function was mainly distributed in the southern areas, and gradually decreased from the southwest areas to the northeast areas. The area of cold spots was higher than that of hot spots and the area of non-significant spots accounted for more than 50% of the total area. This study further showed that the areas with highly important and extremely important degree for water conservation functions accounted for 34.39% of the total area, mainly distributing in the Guanchuan River basin, and the areas with general important and more important degree accounted for 40.59% of the total area, and these areas primarily distributed in the Chengou River and Xi River basin with relatively lower altitude. These results identified the key areas for ecological protection and construction in Anding District of Dingxi City, and provided a decision-making basis for the ecological, social and economic development in the hilly region of the loess plateau.