Based on the biaxial mixing charging system of the firebrick automatic hydraulic press with the maximum pressing force of 25 000 kN, the orthogonal test design method was used to study the influence of the four main design parameters of the charging system on the uniformity of the four mold powders. Based on this rule, a regression analysis was performed. According to the analysis results, the parameters of the biaxial mixing charging system were optimized so that the production efficiency could be improved under the premise of satisfying the uniformity requirements.