In order to improve the electrolyte wettability and thermal stability of polypropylene separator, an Al2O3-coated composite polypropylene separator was prepared with Al2O3 as ceramic particle, polyvinyl alcohol as binder and燿eionized爓ater as solvent through a direct coating process. The bare pp separator and coated pp separator were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), contact angle testing, elecrolyte wettability and thermal resistance testing. It was found that with the Al2O3/PVA layer, the electrolyte uptake of the coated separator increased from 98% to 203%, and the thermal shrinkage in 170℃ for 1 h decreased from 46.1% to 24.4%. Moreover, compared to bare PP separator, the coated PP separator exhibited better discharge C-rate capability and cycling performance when investigated in Lithium-ion Batteries.