It aims to prepare a lightweight wood substitute packaging material using soy protein as the adhesive and study its properties. Lightweight wood packaging material was hot pressed by using different forms and proportions of waste corrugated cardboard and wheat straw as substrate and modified and mixed soy protein isolate (SPI) in different ways as adhesive. Then material properties were tested to determine the optimal formula and process parameters. Selection of modifiers, mixture, substrate and process parameters was closely related to the material properties. When the proportion of NaOH, Ca (OH)2, CMCNa, Na2B4O7•10H2O, SPI, water, paper fiber and straw weight was 0.01︰0.01︰0.2︰0.06︰1︰10︰7︰3, hot pressing parameters temperature at 140 ℃ and pressing time 30 min, the proposal was optimal. Microwave preheating could obviously shorten the hot pressing cycle and improve the sample performance. When the hot pressing time was reduced to 11 min, the density of light wood substitute packaging material was 550 kg/m3, bending strength 18.38 MPa, and elastic modulus 1926.73 MPa, which complied with relevant standards. In conclusion, the modification and compounding of SPI can improve its adhesion and water resistance; microwave heating can improve the thermal efficiency and the sample performance. Therefore, it can be used for the preparation of lightweight wood substitute packaging materials with zero formaldehyde release.