The work aims to investigate the effects of pressure, temperature and moisture content of wet paper embryos on the main mechanical properties of rice straw fiber molded packaging materials, and to determine the weights of each factor and the optimum process parameters. The single factor test method and response surface method were used to determine the optimum process conditions, with the breaking length and bending strength as the evaluation indicators. When the optimum hot-pressing conditions were: hot-pressing temperature of 175 ℃, hot-pressing pressure of 6.9 MPa and wet paper embryo moisture content of 70%, the average breaking length was 7697.93 m, and the bending strength was 72.36 MPa, both of which were close to the theoretical breaking length (7712.62 m) and the theoretical bending strength (71.44 MPa). As a result, the optimized result was credible. The influence of various factors on the breaking length and bending strength of molded packaging materials in the hot-pressing process was: wet paper embryo moisture content> hot-pressing pressure> hot-pressing temperature. In conclusion, excessively high temperatures will cause pyrolysis of hemicellulose, excessively high pressure will cause crushing of the fibers, and excessively high moisture content will lead to excessively high energy consumption. Proper hot-pressing process parameters can reduce energy consumption and ensure the quality and performance of molded packaging materials.