Abstract: Three-dimensional (3D) spacer fabric composite is a new light-weight sandwich structure, the reinforcement of which is integrally woven with a hollow core. A vacuum assisted resin transfer molding (VARTM) process was used for the fabrication of 3D spacer fabric composites with phenolic matrix. The key process problems, such as infusion process, fabric thickness recovery and resin distribution, were investigated systematically, and the influence factors were discussed. The results indicate that higher fiber volume fraction can be achieved for thicker 3D spacer fabric composite. The resin impregnation velocity in the weft direction is larger than that in the warp direction. And heat treatment enhances thickness recovery properties effectively. Besides, high permeability media（HPM） and low viscosity are helpful to resin distribution.