The invention relates to Chestnut cookies and a preparation method thereof. The Chestnut cookies comprise the following ingredients in percentage by weight: 30 to 40 percent of chestnut powder, 15 to 25 percent of salted eggs, 15 to 25 percent of flour, 5 to 10 percent of sweetening agent, 5 to 10 percent of dietary fibers, 1 to 2 percent of seaweed polysaccharide, 1 to 2 percent of grease and water. The preparation process comprises five steps, namely preparing syrup, uniformly stirring egg wash, making a dough, filling stuffing and baking. According to the Chestnut cookies disclosed by the invention, the sweetening agent, such as glucose syrup, stevia sugar or xylitol, replaces cane sugar used in conventional cakes, and the dietary fibers and the seaweed polysaccharide are added into the ingredients, so that the Chestnut cookies have the characteristics of low grease, high fiber, high vitamin and low energy while nutritional ingredients of chestnuts are kept, are particularly suitable for special populations such as fat patients, diabetes patients or patients suffering from cardiovascular disease to eat, have delicate and smooth taste and have crisp flavor.