This paper aims to achieve the goal of reducing the use of packaging materials as much as possible on the premise of meeting the demand of commodities for cartons and not increasing the types of carton specifications through research on the optimization of express carton specifications. According to the actual demand of the commodities for express cartons, the objective function is minimized total amount of corrugated paper used, and the matching relationship between the commodity and the carton specifications is used as the constraint condition, to establish an optimization model. The solution algorithm obtained by fusing artificial fish swarm algorithm and simulated annealing algorithm is used to solve the model. In the simulation experiment, the carton specification optimization scheme obtained by using the modeling solution method proposed in this paper saves 23% of corrugated paper compared with the current carton specification system of China Post Group Corporation, while the carton specification optimization scheme obtained by k-means cluster analysis only saves 11% of corrugated paper. The method proposed in this paper can meet the needs of express carton specifications optimization in an e-commerce environment featured by small batch size, many types, different sizes, and dynamic updates, helping reduce the excessive use of packaging in the express industry.