This work prepares biomass packaging material with wastepaper fiber and crop straw as the main raw material based on extrusion processing, studies the main factors that affect the mechanical properties of the samples and recommends the optimal formula. Wastepaper fiber and crop straw were used as the main raw material in this article, and the raw material was stirred and mixed with a certain amount of starch, glycerin and PVA. And then the biomass packaging material was made through extrusion processing in order to realize the continuous production of the environmental protection packaging materials. On the basis of single factor experiment, how the mechanical behavior of materials was influenced by the ratio of base material, starch content, the content of PVA and the glycerol content was investigated by the orthogonal experiment. The results showed that the starch had good compatibility between wastepaper fiber and crop straw after 15 min water heating under the condition of 85 ℃. The degree of the four factors’ impact on the compressive properties was: starch content > PVA content > the ratio of base material > glycerol content. The degree of the four factors’ impact on the flexural behavior was: starch content > the ratio of base material > PVA content > glycerol content. In conclusion, the production of biomass packaging materials through extrusion processing depends on dispersible uniformity and viscosity of the mixing materials, which use the wastepaper fiber and crop straw as the main raw material. The mechanical properties are better when the ratio of base material is 2︰3 (mass ratio), PVA 2.5%, starch 9%, and glycerin 5%.