To improve the distribution properties of nanoparticles in the polymer electrolyte, micro-porous polymer electrolyte PVDF-HFP-SiO₂(OP-10) was prepared with phase inversion method by adopting nano-sized SiO₂ as the inorganic filler and OP-10 as dispersant. The morphology, crystal structure and electrochemical properties of the electrolyte were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), electrochemical impedance spectra (EIS). The results showed that the addition of nano-SiO₂ suppressed the crystallinity of polymer electrolyte and enhanced the tensile intensity. The ionic conductivity was improved, the highest ionic conductivity (20 ℃） of the PVDF-HFP-SiO₂(OP-10) polymer electrolyte was 490×10-3S·cm-1,with a high electrochemical stability window of 53 V, and the corresponding cation transference number was 083. The distribution of SiO₂ and interfacial compatibility of nanometer particles were improved by the addition of OP-10.