Abstract: In this study,polyvinyl alcohol(PVA)was used as the research object. PVA membrane materials were crosslinked with citral and nano-SiO₂ to improve the water resistance,and the structure of the modified membrane materials was characterized. The results showed that citral and nano-SiO₂ could significantly reduce the swelling rate and water vapor transmittance of PVA membrane materials,and when the addition of citral and nano-SiO₂ was 3.93 mL/100 mL and 0.62 g/100 mL,respectively,the water vapor transmittance of PVA membrane material was the lowest,which was(768.73±20.51) g/(m²·d).The results of water contact angle,scanning electron microscopy,infrared spectroscopy and X-ray diffraction showed that citral and nano-SiO₂ can be filled into the PVA film materials uniformly by chemical cross-linking method under the above conditions. The water contact angle can be reduced and the structure and crystalline properties can be changed. The water resistance of the composite film materials can be significantly improved.