Production-distribution joint optimization can enhance overall supply chain efficiency and reduce operational costs. Equipment reliability is a key factor affecting the production supply of manufacturing firms, thereby influencing downstream distribution. A well-planned preventive maintenance strategy can effectively enhance equipment reliability, increase production capacity, reduce distribution costs, and ultimately lower overall supply chain costs. Thus, production-distribution joint optimization model based on preventive maintenance strategies was established, in which preventive maintenance frequency and distribution routes were optimized by genetic algorithm, aimed at minimizing the total costs of maintenance and distribution. And the functional relationship between preventive maintenance and production capacity was defined, using production volume as the supply. Some conclusions were obtained from the results of the experiments. First, higher demand leads upstream firms with lower single preventive maintenance costs, higher single corrective maintenance costs, and higher failure rates to perform more preventive maintenance. Second, the number of preventive maintenance, maintenance cost, and routing cost all exhibit a positive correlation with demand. The research results have enriched the theoretical research in the field of production distribution and provided decision-making basis for the practical activities of enterprise production distribution.