The porous material is a fully degradable and environmentally friendly material prepared by freeze-drying, using starch as the main raw material, sisal fiber as the reinforcement, water as the foaming agent, and glycerol as the plasticizer. The porosity mechanism was explored, and the processing procedure was clarified. Through infrared spectroscopy analysis (FTIR), scanning electron microscope characterization (SEM) and expansion rate test of the samples, it was found that compared with the porous materials by extrusion and injection molding methods, the porous material samples by freeze-drying method had smaller cell size and thicker pore walls. The addition of glycerol, water and sisal fibers had an effect on the expansion rate of starch-based porous materials, the expansion rate gradually increased with the increase of sisal fibers dosage, and the expansion rate increased first and then decreased with the increase of glycerin and water dosage. When the dosage of starch was 500 g, 250 g of sisal fiber, 200 g of glycerol and 250 g of water were added, the expansion rate reached a maximum value respectively. Using the freeze-drying method to prepare starch-based porous materials can effectively avoid the problem that starch is difficult to hot melt. The process is simple and the equipment is cheap. It can provide a new idea for the practical production and application of starch-based porous materials in foam, gel and other products.