Airflow atomized powder technology is widely applied in the field of production of powder metallurgy, in order to improve the shearing action of airflow on metal flow, according to the compressed air which is formed by the expansion of the high-speed airflow dynamics principle, a girth airflow atomized powder nozzle is designed. The influence of parameters in the crushing process of girth airflow atomized powder nozzle was analyzed. The mathematical expression of the diameters that compressed air flowing in the intake pipe without turbulence was given out. And the ratio of the R0/re and pe/p0 that affected airflow velocity of girth exports were analyzed, and the crushing effect of powder was improved by increasing the ratio of the R0/re or reducing the ratio of the pe/p0. The mathematical expression of the design computation for atomizing cone-angle was established. Inside the nozzle flow field obtained by simulation was divided into four areas: eddy zone, reflux area, separation area and mixed area. The simulation results verify the accuracy of parameters selection, which provides a theoretical basis for the design of girth airflow atomized powder nozzle.