In order to optimize the process parameters of the mechanical properties of PP/corn straw composites and further optimize the preparation process, the orthogonal test design of L ₁₆(4⁴) was used to prepare PP/corn straw composites under different process parameters. The effects of wood-plastic ratio, hot pressing temperature, hot pressing time and hot pressing pressure on the mechanical properties of PP/corn straw composites were analyzed. The results showed that the wood-plastic ratio had the greatest influence on the mechanical properties of PP/corn straw composites among the four factors of wood-plastic ratio, hot pressing temperature, hot pressing time and hot pressing pressure. Secondly, the hot pressing pressure has a great influence on the flexural strength and impact strength of PP/corn straw composites, and the hot pressing temperature has a great influence on the tensile strength of PP/corn straw composites, the hot pressing time has the least influence on the properties of PP/corn straw. When the ratio of wood to plastic is 4∶6, the hot pressing temperature is 185 ℃, the hot pressing time is 10 min, and the hot pressing pressure is 2.5 MPa, the flexural strength is the maximum value of 39.58 MPa, and the impact strength is the smallest. When the ratio of wood to plastic is 4∶6, the hot pressing temperature is 185 ℃, the hot pressing time is 15 min, and the hot pressing pressure is 2.5 MPa, the tensile strength is 17.18 MPa. When the ratio of wood to plastic is 3∶7, the hot pressing temperature is 190 ℃, the hot pressing time is 15 min, and the hot pressing pressure is 2.5 MPa, the impact strength is the maximum value of 3.94 kJ/m², and the flexural and tensile strength are the smallest. By comparing the mechanical properties of these three processes, without considering the focus, the optimal preparation process was obtained as follows∶wood-plastic ratio 4∶6, hot pressing temperature 185 ℃, hot pressing time 15 min, hot pressing pressure 2.5 MPa.