In this paper, the pith of sunflowers was used to be the main raw material. Therefore, the properties of the biodegradable packaging materials were studied. The quantity of starch and density of PVA were changed under the condition of 20% content of PVA, the hot-pressing time for 15min and the pressure of 1.19Mpa. The orthogonal experiment was made under the above conditions. It got the conclusion that the thickness of the plank is 1.65 mm. Its density is 0.80 g/cm3. According to GB/T12941-2008 and GB/T 2679.7-2006, the mechanical properties of the material meet the relevant standards.