High silica glass fiber/phenolic composites were prepared by thermal expansion molding (SRTEM) with silicone rubber.Morphology of the fracture surface was characterized by scanning electron microscopy.The porosity and performances between SRTEM and traditional molding composites were compared.The variation coefficients of density and tensile strength were analyzed.The results show that the SRTEM composites have higher surface gloss, and its porosity is low and close to 0.The variation coefficient of density is 0.09,and the variation coefficient of tensile strength is 1.95% and lower than that of traditional molding composites.