In order to improve the continuity and stability of 3D printer wire, a collaborative optimization method of wire feeding mechanism and nozzle was proposed, which overcome the deficiency that the nozzle and wire feeding mechanism of printer are optimized separately while the coupling effect between them is ignored.Taking the heating section length, the cooling section length, the outlet length and the wire feeding speed as the optimization parameters, and taking the average velocity and average temperature of the nozzle section as the optimization objectives, the orthogonal test was designed and the fluid simulation was carried out.In order to quickly obtain the optimal scheme, neural network and NSGA-Ⅱ algorithm were used to optimize the analysis. The results show that when the heating section length is 6 mm, the cooling section length is 4 mm, the outlet length is 07 mm, and the wire feeding speed is 45 mm/s, the maximum average velocity of the nozzle section is 78 mm/s, and the maximum average temperature is 20839 ℃.The maximum average speed and maximum average temperature are increased by 26% and 122% respectively.Finally, fluid simulation was carried out by using the optimized combination of process parameters. The results show that the average velocity and temperature of nozzle section are obviously improved.