Abstract: The tensile properties of short PET fiber/wollastonite/silicone resin hybrid composites have been studied. It was observed that the addition of wollastonite whisker with relatively low volume fraction to PET fiber/silicone resin system would lead to a reduction in the tensile stress of the hybrid composites. But when a very high amount of wollastonite was added, for example, 38% volume fraction, tensile strength of the hybrid composite increased sharply, which was even higher than that of PET fiber/silicone resin composites with the same fiber loading. The tensile modulus was found to increase as the volume fraction of PET fiber in the hybrid composites increases, while the wollastonite loading had little effect on the tensile modulus of the hybrid composites. The change of PET fiber efficiency factor with the addition of wollastonite to PET/silicone system was presented quantitatively.