Abstract: Poly(vinylidene fluoride) (PVDF)silica(SiO2) composite hollow fiber membranes were prepared by phase transition process. The microstructure, chemical composition, thermal stability, mechanical strength, hydrophilicity, separation performance and antifouling ability of the membranes were characterized by scanning electron microscopy (SEM), energy dispersion of X-ray (EDX), Fourier infrared spectrometer (FT-IR), thermogravimetric analysis (TGA), mechanical property test, contact angle measurement and ultrafiltration (UF) experiment. The results showed that crystal structure of PVDF underwent a transition from α-phase to β-phase due to the addition of SiO2. Compared to those of the pure PVDF membrane, the performances of composite membranes improved greatly. When the mass fraction of SiO2 was 3%, particles uniformly dispersed and the break strength of the composite membrane was 2.7 times higher than that of the pure PVDF membrane. Pure water flux increased from 81.6 L/(h·m2) of the PVDF membrane to 160.0 L/(h·m2). Moreover, the thermal stability, hydrophilicity and antifouling properties were enhanced significantly. However, excess amount of SiO2 (w>3%) led to particle aggregation and the decline of the performance of the composite hollow fiber membranes.