Abstract: ZnO porous films were prepared on glass substrates by PEG-assisted sol-gel method using Zn（CH₃COO）₂·2H₂O as precursor,ethanol as solvent and NH（C₂H₂OH）₂ as chelating agent.The characteristics and microstructure of films as well as the chemical and physical changes taken place during sol-gel and heat treatments were analyzed by IR,TG-DTA,XRD and SEM.The effects of precursor concentration and PEG content on the characteristic of films were discussed.The results show that ZnO porous thin films can be prepared based on the admixture of PEG and in water bath at 70℃,pore size and density are increased with the addition of PEG,when Zn²⁺ concentration is 0.6mol/L.