The invention belongs to the technical field of food producing, and provides a preparation method of a sucrose-free nougat. According to the preparation method, no white granulated sugar or other reducing sugar materials are added, a plurality of editable sugar alcohol materials are used for providing sweetness, and the sugar content (by glucose) of each kind of the editable sugar alcohols is controlled to be 0.5g/100g or lower, and no sugar material is added (GB 13432-2004). Each 100g of the sucrose-free nougat contains 5g or less total sugar (by glucose), the sucrose-free nougat is a low-sugar low-energy product (GB 13432-2004), is low in sugar content, low in calorie, and is capable of protecting teeth; no obvious influence on plasma glucose and insulin level is observed; the sucrose-free nougat can be eaten by patients with diabetes, is soft and puffed in texture, fine and smooth in structure, moderate in hardness, is fragrant and sweet, is thick in milk fragrance, and possesses excellent soft chewable mouthfeel.