All-solid-state lithium-ion batteries constructed with solid-state electrolytes have extremely high safety and reliability, which are an existing research hotspot in lithium-ion batteries. It is thus a great significance to develop inorganic-polymer composite solid electrolytes. In this paper, Li7La3Zr2O12 (LLZO) nano-powders were prepared by a sol-gel and ball milling method. Also, a solid-state composite polymer electrolyte with LLZO as an active filling material and polyethylene oxide (PEO) blended with polyethylene partial fluoride (PVDF) was prepared by a solution pouring method. The samples were characterized by field emission scanning electron microscopy and X-ray diffraction. The results show that LLZO/PEO/PVDF solid-state composite polymer electrolyte (SCE) membrane with 10% (in mass fraction) LLZO has a high ionic conductivity (8.93×10-5 S/cm) and a stable electrochemical window (4.9 V). The rate capabilities and cycle performance of LiFePO4/Li all-solid-state lithium battery with 10%LLZO both are improved. At 60 ℃, the capacity recovery rate is 99.4%, and the capacity retention rate after 100 cycles is 84.1% at 0.2 C.