The invention discloses a preparation process of a sweet potato dietary fiber French roll and belongs to the technical field of bread processing. According to the preparation process of the sweet potato dietary fiber French roll, sweet potatoes are processed into the French roll through the steps of mashing and the like. The preparation process of the sweet potato dietary fiber French roll has the advantage that, through combination of the steps of mashing the sweet potatoes and mixing the mashed potatoes with cane sugar, flour and yeast liquid, the obtained French roll obtains the unique flavor and the nutritive value of the sweet potatoes and meanwhile is good in color, flavor and taste, delicious and delicate in sweet and sour taste and capable of achieving the healthcare value of preventing cancers and cardiovascular diseases, thereby being high in marketing potential.