Biodegradable buffer materials are yhfriendly to the environment and better suited for a number of applications. Many factors affect properties of biodegradable buffer materials. They can generally be divided into technological factors and formula factors. Elasticity and tensile strength are two indicators of quality. Through experiments study, the starch granules are initially fragmented, and then under temperature and shearing by the extrusion. Starch is destructured, plasticized and melted. The elasticity and the tensile strength of the composite material were got. Combination of technological factors include screw configuration, screw speed and die temperature; formulations include foaming agent, filling dosage, and so on. The results showed that each factors had different influences on the properties of the biodegradable material.