Abstract: The secondary structural features, such as channels between pultruded plates, significantly influence the vacuum-assisted resin infusion process and resin distribution at the bonding interface of the pultruded spar cap in wind turbine blades. However, these features are often overlooked in process optimization due to the lack of effective consideration methods. This study systematically investigates the impact of secondary structural features on the molding process. Firstly, through factory surveys, key secondary features affecting the process were identified, and a laboratory-scale vacuum infusion experimental method was established. Secondly, an analytical model for the equivalent permeability of channels between pultruded plates was derived, and a refined numerical method to model the infusion process was proposed. This method effectively simplifies the free flow-porous medium coupling flow problem in the resin infusion process into a homogeneous porous medium seepage problem, which was validated through experiments. Finally, the numerical analysis method was employed to optimize the infusion strategy. The study reveals that the nesting effects of the vacuum bag, channels between pultruded plates, and fabrics significantly affect the resin flow rate across the upper and lower surfaces of the mold and the resin filling time. The optimized numerical method improves both simulation efficiency and accuracy, showing good agreement with experimental results, with a mold filling time deviation of approximately 5.65%. This approach can effectively guide the design of the infusion process. Additionally, the surface venting strategy on the top surface was able to control overall porosity below 7% and local porosity below 2%.