The micro structures of biomass cushion packaging products were studied using SEM and EDS technology. The experimental results showed that bubble structure is formed in biomass cushion packaging products when using molded foam molding process; the shape of the bubble structure is not only relevant to component matching, but also to molding process; when the content of straw fiber is 10% and the molding temperature is 225 ℃ , the products' rebounding rate is 89% ; plant fiber forms three-dimensional mesh structure in the products, which is irrelevant to the content of plant fiber and starch; Three typical forms exist in the surface of production, such as white particles, horizontal strip, group black areas, which have the main components of infilling, plant fiber, and starch respectively.