Abstract: Two kinds of special tackifiers LSG-1 and LSG-2 were studied, which would be applied in resin transfer molding (RTM) technique to prepare 5284 resin composite. On the basis of analyzing the processing conditions and properties of the matrix resin, the ingredients of tackifers were preliminary determined. By testing the viscosity of the tackifier, 5284 resin and the compatibility between the tackifier and the matrix resin 5284 , the processing condition was determined. The springbacks of U-shaped bending and compression were combined with the microphotograph of the distributing condition of the tackifer to investigate the shape-fixing performance of the tackifier. The preform was fabricated by using the tackifier, and the influences of tackifiers on the processing properties and mechanical performance were studied by testing permeability of preforms and mechanical properties of the composite. The result s show that the tackifier has a satisfactory compatibility with the matrix resin, would not have any negative effect on the composite, and makes the preform have a favorable shape-fixing result .