Abstract: Numerical simulation was conducted for the flow and heat transfer process of the mixing flow in the test duct of the icing wind tunnel,where the temperature of air was low but that of the sprayed water was high to keep the nozzles from freezing.A simplified model based on Lagrangian method was built and solved,whilst the model of droplet size distribution,the phase transmission model of water freezing and solidification,the heat and mass transfer between air and water/ice droplets were considered.The variation of temperature,humidity and velocity of air and the temperature,radius and velocity of droplet during the flow process was obtained under different conditions.Furthermore,the patterns about how initial parameters affect the finial flow were achieved.This model and conclusion were validated by comparison with current literatures.