Urban planning faces challenges that necessitate efficient urban space utilization. Low hydrogen-doped natural gas pipelines in cities pose explosion risks to underground spaces with diverse rigid and flexible facilities. This study simulates urban underground space explosions using a bottom-end ignition experiment. By adjusting flexible facility thickness and blockage rates, the research investigates protective strategies against low hydrogen-doped methane explosions. Thinner flexible facilities with lower blockage rates demonstrate superior explosion mitigation capabilities compared to rigid structures. Notably, flexible facilities play a crucial role in reducing explosion intensity, flame speed, and overpressure. The study reveals that a proper blockage rate in flexible facilities can mitigate explosion impacts by disrupting flame vortexes and altering pressure wave angles, thereby safeguarding rigid structures. Overall, the findings emphasize the importance of strategic deployment of flexible facilities to enhance urban safety and minimize explosion risks in urban underground spaces.