Abstract: Aiming at the problem whether the adsorption of SF₆ gas by polyurethane used for pouring and fixing the current transformer (CT) has an effect on leakage detection of gas-insulated metal-enclosed switch (GIS) products, samples were prepared and the adsorption capacity of polyurethane to SF₆ gas was study, and it was also compared with that of epoxy resin. The results show that the adsorption capacity of polyurethane to SF₆ gas is much higher than that of epoxy resin, and the adsorption capacity of polyurethane to SF₆ gas increases with the increase of foaming amount of the polyurethane. Therefore, when using the dressing method to detect the leakage of GIS products, it is necessary to consider the influence of the adsorption of pouring material polyurethane to SF₆ gas and take measures to avoid misjudging product leakage.