Abstract: In order to investigate the effect of coating polymer film on the performance of gas diffusion electrode, two kinds of polymer solution were coated on the waterproof breathable layer respectively, and rolling method was used to prepare gas diffusion electrode. Testing of selectivity to O2 and H2O vapor, the capability of gain and loss water and discharging capability of AA size zinc-air battery specimen which contained this gas diffusion electrode were carried out. Results show that after coating PDMS solution, the separation coefficient to O2 and H2O vapor of gas diffusion electrode reached to 2.11; the working life of AA size batteries specimen which contained this gas diffusion electrode was greatly prolonged, wherever in a dry environment or in a moist environment, and effective utilization ratio of zinc electrode was greatly improved, too.