The invention is suitable for the technical field of nutritious food, and provides a composition of low GI potato bread. The composition comprises the following components: wheat flour, potato flour,purple potato flour, maltitol, erythritol, inulin, a polyphenol extract, yeast powder, salt, butter, coconut oil, an egg liquid, a compound modifier and water. Aiming at the defect of high GI value ofcommon wheat flour bread, the low GI potato bread is researched and developed through adjustment of the composition; by adopting potato powder, purple potato powder, sugar alcohol and particularly adding inulin dietary fiber, the low GI potato bread not only has a good supplement effect in the aspects of minerals, vitamins, essential amino acids, dietary fiber and the like, but also a low GI bread product is obtained through reasonable compatibility of raw material components; and the bread does not cause rapid fluctuation of blood sugar after being ate, so that the bread not only can meet the nutritional requirements of common diets of eaters, but also has obvious improvement in the aspects of bread calories, flavor and nutritional value.