Abstract: Polycrystalline nano-ZnO thin films on quartz substrates were prepared by sol-gel process.Structural features,surface morphology and UV absorption spectrum were studied by XRD,AFM and UV-Vis spectrophotometer.The influences of annealing temperatures,degradation temperatures,original concentration of phenol and air flux on photocatalystic properties of ZnO thin films were investigated.And the activity loss and resurrection of photocatalystic properties were also studied.The results show that the photocatalytic properties of nano-ZnO thin films prepared by sol-gel are efficient and recyclable.