Abstract The detection of trace impurity gases in fluorinated gas (F‐gas) that are widely used in the industry offers a significant avenue for equipment status monitoring and mitigating unnecessary emissions. However, the formidable electron affinity (EA) and adsorption propensity of F‐gas molecules render the identification of trace impurities within a high‐concentration F‐gas atmosphere exceptionally challenging. Herein, the filtration‐sensing strategy is proposed to realize highly sensitive and selective Room Temperature (RT) sensing of trace gases in the F‐gas environment. Through the innovative construction of a bilayer structure, comprising Co 3 (HITP) 2 as the overlayer and SnO 2 nanofibers (NFs) as the sensing layer, remarkably sensitive detection of trace impurity gases under intense F‐gas interference conditions is achieved. The efficacy of the Co 3 (HITP) 2 overlayer is further corroborated through the incorporation of Pd‐SnO 2 and MoS 2 ‐SnO 2 sensors, concurrently facilitating targeted quantitative identification within a complex gas mixture environment. The underlying sensing mechanism is predominantly attributed to interatomic adsorption interactions and the modulation of gas diffusion by microporous structures. This work provides pioneering insights into trace impurity detection within high‐concentration F‐gas atmosphere while presenting a potentially viable solution for the operational maintenance of F‐gas‐based industrial equipment (F‐equipment) in industrial applications.