Hydrogen (H₂) has gained increasing attention as a low-carbon and sustainable energy source. Because of its high flammability above 4%, precise and reliable detection is crucial for safe production, handling, and practical use. However most conventional H₂ sensors are affected by reducing gases and humidity changes, which severely degrades sensing accuracy and long-term stability. To overcome these challenges, we synthesized crosslinkable polymers containing fluorinated monomers to fabricate membranes with high H₂ selectivity. These membranes act as molecular sieves, selectively allowing H₂ transport while minimizing interference from moisture and reducing interfering gases. As a result, sensors integrated with these membranes exhibit stable and consistent performance across a wide range of relative humidity conditions. This study provides new insights into the design of H₂-selective membranes and advances reliable H₂ sensing technologies for diverse industrial applications.