The work aims to conduct a numerical simulation analysis on the flow field near the air nozzle of package printing equipment, and then optimize the angles of outside air nozzle according to the results. With the calculation of fluid mechanics as theoretical basis, model building, grid division, numerical calculation and feature evaluation were conducted according to the oven structure of the actual equipment, to analyze the characteristics of flow field. With the printed material surface as the basis, the optimal parameter range was determined. The distribution of the flow field between the air nozzle and the printed material was obtained. Moreover, an overall evaluation for the temperature field, velocity field and pressure field of the printed material surface were made. The major characteristics, such as mean value, variance and range, were obtained. As for the arrangement structure of the air nozzle, the angle of outside air nozzle has a significant influence on the temperature field, velocity field and pressure field. The best angle is near 150° or 120°, and it should not occur around 135°.