Abstract: The residue of sweetpotato was used as raw material in this paper.Comparing and analysing the physiochemical properties and structural properties of dietary fiber, the dietary fiber were got though different cooking technologies.The cooking technologies included atmospheric cooking, high pressure cooking, microwave cooking and extrusion cooking, which improved the water holding capacity, swelling capacity, glucose absorption capacity and content of dietary fiber, decreased its oil holding capacity and fat absorption capacity.In four kinds of cooking technologies, extrusion cooking was the most significant. The results of structure analysis showed the chemical structure of dietary fiber were not been destroyed, while their surface structure have been broken and increased the crystallinity of dietary fiber.