The internal flow field of the nozzle was simulated and analyzed based on the VOF multiphase flow model of Euler-Euler method with Fluent software. On the basis of determining the optimal structure of the nozzle outlet section, the external atomization jet region of the nozzle was analyzed by using the DPM model based on Euler-Lagrange method, and the atomization mechanism of the nozzle was explored. The results show that the nozzle has the best performance when the exit cone angle θ=51° with the average velocity of 101.19 m/s and turbulence intensity of 2 141.1%;the nozzle has the best performance when the exit length L2=20 mm with the velocity of 101.03 m/s and turbulence intensity of 2 121%;the nozzle has the best performance when the outlet diameter d2=25 mm and the average velocity is 101.49 m/s and the turbulence intensity is 2 101%, and the outlet diameter d2 has the greatest influence on the atomization performance of the nozzle.According to the optimized structure size, a 5∶1 scale reduction experiment was carried out to verify the four point distribution of the liquid phase flow in the nozzle. Meanwhile, the error between the cone angle of the atomized droplet distribution outside the nozzle and the simulation result is 3.81%, and the maximum error of the atomized droplet size is 3.67%.