Abstract: With the rapid development of FDM 3D printing technology, various industries have high requirements for printing efficiency and molding accuracy. For the problem of insufficient molding accuracy in FDM 3D printers, a consistency analysis was conducted on the error factors that affect the processing accuracy of 3D printers. The feasibility of error consistency analysis and optimization design was verified by establishing a model. This study provides a new theoretical design method for improving the accuracy of FDM 3D printers, which has reference value for enhancing the processing accuracy of 3D printers, improving the surface quality and dimensional accuracy of molded parts.