Environmentally friendly polyvinyl alcohol (PVA) has a broad range of potential applications in membrane science. This article describes the co-crosslinking used to adjust the water resistance and swelling level of PVA molecules and broaden their applications. To integrate functional groups and carbon chains in the PVA matrix, the crosslinking agents glutaraldehyde (GA) and ammonium persulfate (APS) were used, the complexity of the PVA crosslinking structure can be dramatically increased. The results showed that the crosslinked PVA film's water resistance and thermal stability qualities have improved. The synergistic crosslinked film's swelling percentage, maximum decomposition temperature, and diffusion constant altered from 590%, 242.9℃, and 1.13×10^-11 m²/s to 129%, 344.7℃, 0.02×10^-11 m²/s respectively. The synergistic crosslinked film's swelling percentage, maximum decomposition temperature, and diffusion constant were altered with the molecule structure design. This method can give a novel reference to the performances design of hydrophilic polymers in different applications.