Abstract: The structure and working principle of atomizing nozzle by circular seam air impact were analyzed, the numerical simulation model on flow field distribution of atomizing nozzle was studied, and the effects of inlet pressure and circular seam inclination on velocity distribution in flow field were investigated. The results show that, the acceleration of air velocity remains unchanged from the inlet of intake pipe to the exit of air impact atomizing nozzle, and the maximum is achieved at 80 mm away from the center line of intake pipe inlet. With the increasing of inlet pressure, the exit velocity of air impact atomizing nozzle shows an increasing trend obviously, and the error between simulation results and theoretical calculation result is within 10%. With the increasing of circular seam inclination, the negative pressure eddy current is gradually closed to the import of powder tube, the maximum velocity in backflow zone, separation zone, and mixed zone increases monotonously. Considering the air impact effect and jet velocity, the optimal circular seam inclination is determined as 50°~60°.