Abstract: Based on resin transfer molding (RTM) process, a composite wing was fabricated. Aiming at the dry spot defect of the wing, PAM-RTM software was used to analyze the formation of dry spot. Because of the high volume fraction of fibers in the junction area of upper and lower wings and leading edges, the resin permeability in this area was lower than that in other areas, thus the envelope phenomenon appeared and the dry spot was formed. Two kinds of improved injection ways were designed to reduce the dry spot area. By comparison, it is found that the dry spot area produced by the front line injection method is significantly smaller, but the injection time increases. The resin viscosity can be reduced by increasing the injection temperature, thus the filling time is reduced. At the same time, the injection time can be further reduced by controlling the opening and closing of the outlet.