The performance of the dry ice spray gun directly determines the effect of dry ice cleaning.In view of the poor cleaning performance of an existing dry ice cleaning spray gun,the multiobjective optimization for the spray gun was carried out by taking multiple cleaning influence factors into account to improve the cleaning effect.The geometric characteristics of the spray gun were used as variables to design the orthogonal experiment.The simulation experiment was carried out by using FLUENT.The single target was optimized separately.The membership function was established according to the obtained single target optimal value to complete the dimensionless processing,and the single target optimal value was weighted to obtain the comprehensive evaluation score to evaluate the comprehensive performance of spray gun.By analyzing the extreme difference of the comprehensive performance,the influence divension of each geometric parameter of the spray gun structure on the single target and the comprehensive performance was obtained.Finally,the design scheme of the spray gun with the best cleaning effect was designed.The test results show that the comprehensive performance of the optimized spray gun is 2.34 times higher than that of the existing spray gun;the gassolid twophase coupling simulation experiment based on FLUENT combined with comprehensive evaluation method can be used to effectively optimize the dry ice cleaning spray gun.The research results provide reference for the design optimization of the spray gun.