Taking the airpurged nozzle in the galvanized steel pipe purging system as the research object, the mathematical model of the purge jet was established, the inner contour line was described by quartic Bspline curve, and the exit of the nozzle was described by ellipseshaped section. Based on the S-A turbulence model, the Fluent software was used to simulate the slot nozzle flow field. In order to study the influence of the incident angle and purge distance on the purge flow field, the impact force at the inlet angles of 30°, 45°, 60°, and 90° under different inlet pressures was analyzed. The influence of purge distance change on the impact force was studied.The results show that the pressure hitting the wall, the jet velocity and the gas curtain width of the designed nozzle are greater than that of the traditional nozzle and the sweeping effect is improved.