The work aims to study the flow field characteristics of entrained air between web and guide roller at different moving speeds. The motion characteristics of web and guide roller and the forming mechanism of entrained air between them were analyzed to complete the modeling of flow field of entrained air. Numerical simulation of the flow field of entrained air between the moving web and the guide roller was carried out. In combination with the actual circumstances of the engineering, the law of flow field characteristics changing with the web moving speed was analyzed and discussed. With the increase of the web moving speed, the volume of entrained air increased accordingly and the flow speed distribution range in the wedge-shaped entrance area was enlarged. In the wrap angle exit area, the outflow speed and the flow path were increased. Web moving speed is the main factor influencing the flow field characteristics of entrained air. The entrained air forms local vortexes in the entrance area. Vortex can cause unsteady flowing state and will thus cause web flutter.