In order to improve the water vapor barrier property of zirconium film adhered to rigid polyurethane foam plastic, a method of the combination of plasma cycle etching and middle frequency magnetron sputtering technologies is proposed by changing the growth mode of zirconium grains. The grain on the surface of the zirconium film exhibits a trend of non crystallization after plasma cycle etching. A kind of normal columnar crystals is found in the cross sectional morphology for the non-etched sample, but a hybrid of columnar crystal and small groups of spherocrystal is observed for the etched sample. Finally, the water vapor barrier properties of zirconium film can be improved by the ion source cyclic etching. The normal columnar crystal growth of the zirconium film is inhibited by the cyclic etching, making the grain more refined, and the film shows a trend of non crystallization, which is regarded as the fundamental reason for the increase of compactness and improvement of water vapor barrier property.