The overall structure of the biological printer based on chitosan was briefly introduced, and the structure design of the printer nozzle was carried out. According to the flow characteristics of chitosan solution in the nozzle, finite element simulation of flow channels in four common nozzles was carried out, and one nozzle with the optimal internal structure was selected. The nozzle with the optimal internal structure was analyzed, and the structure of the nozzle with the optimal internal structure was optimized according to the analysis results. The optimized nozzle was simulated by using finite element method. The results show that the maximum pressure inside the nozzle is reduced after optimization. This study provides reference for improving the molding process of the biological printer based on chitosan.