Vacuum-assisted Resin Transfer Molding (VaRTM) is a process of vacuum infusion as a closed molding, where the fiber reinforcement is compressed with outer atmospheric pressure and tightened against the rigid mold surface. In the VaRTM process, the vacuum expels air and VOC from the preform assembly and allows the resin to impregnate dry preforms and the compression force to compact the composite to the desired volume fraction of the reinforcement to the matrix. Thus, much thinner and more flexible composite can be produced with high volume fraction of fiber reinforcements. In this study, ultrahigh molecular weight polyethylene (UHMWPE) fabrics reinforced composites were used for the VaRTM processing, and a VaRTM system was equipped with a self-designed mold attached. UHMWPE fabrics were produced by 2D-weaving and 3D-knitting, which had characteristically high tenacity, high modulus and low specific gravity as low as 0.97. In the VaRTM process, the impregnation of UHMWPE fabrics by resin was influenced by several processing factors such as resin type and viscosity, resin curing temperature and time, fabric structure, fabric layers and thickness, etc. Resins were determined for UHMWPE fabric preforms through preliminary tests. Morphology, mechanical and thermal properties of the composites were examined to study the effect of processing conditions in the VaRTM process.