This study focuses on enhancing the sensitivity of a gas volume fraction sensor and mitigating fiber intermode inter- ference through the design of a double- channel edge hole structure.using COMSOL software,a gas volume fraction sensing model and loss spectrum are established to investigate the impact of varying structure parameters and fiber birefringence thick- ness.The results show that the sensor achieves high sensitivity,with 0.36nm/% for hydrogen and 2.89nm/% for methane,demonstrating eXcellent linearity.The photonic crystal fiber gas sensor eXhibits superior sensitivity,rapid response time,and the ability to detect multiple gases simultaneously.This research offers insights for developing sensitive films in real-life and in- dustrial applications,as well as single fiber sensors capable of detecting three or more gas volume fractions accurately.