Using gelatin and pregelatinized starch as raw materials to prepare biodegradable foam materials with cushioning effect, which provides a new option for biomass foam for cushioning packaging. Through the experimental study of different gelatin starch mass ratio, solid content and twelve alkyl sulfate (SDS) dosage, the structural characterization and static compression properties of the foam materials were comprehensively evaluated. The composite foams prepared from gelatin and pregelatinized starch have low apparent density and good cushioning properties. The single factor experiment showed that starch had a strong mechanical effect on foam. The optimum conditions for gelatin starch buffer foam are solid content 20%, surfactant content 0.75%, gelatin Starch Ratio 70∶30. Under the optimal conditions, the foaming ratio of gelatin starch buffer foam is 5.14 times, the apparent density is 0.064 g/cm3, the elastic modulus is 36.64 kPa, and the 50% compressive strength is 2.49 kPa.