The work aims to design a cushioning structure of packaging box based on low density polyethylene to satisfy the design requirement of impact acceleration. The maximum acceleration-static stress curve of low density polyethylene was used for theoretical calculation, and an initial model of cushioning structure of the packaging box was designed. Ansys Workbench (finite element simulation software) was applied for the horizontal drop simulation of the whole packaging box and the simulation result was analyzed. When the design thickness of cushion was 75 mm, the maximal impact acceleration of the whole packaging box was below 40g after its drop, which satisfied the design requirements. The cushioning structure designed based on the low density polyethylene material can provide effective cushioning for the packaging box, and the cushioning property satisfies the requirement.