The work aims to optimize the design of spindle structure of carton forming machine based on the TRIZ theory. The spindle structure of carton forming machine was analyzed and summarized based on the conflicts of the TRIZ theory, to obtain the corresponding innovation design principle and optimization direction. The optimal innovation principle was selected through analysis and comparison to solve the conflicts in the solution design. The optimization design provided by the TRIZ theory was applied to conduct the finite element analysis on the spindle structure. The optimization scheme and direction of the spindle structure of carton forming machine were obtained through the TRIZ theory. The maximum deformation of the spindle structure of the carton forming machine was 0.1796 mm, obtained through the further analysis with the finite element simulation software. The maximum deformation of the spindle structure was 0.18 mm, obtained through the experimental verification of the ultimate optimization scheme of the spindle structure of carton forming machine, which met the usage requirements. A new idea is provided for the optimization design of the spindle structure of carton forming machine by combining the TRIZ theory with the finite element method, and the basis is provided for the further optimization design of the spindle structure of carton forming machine.