Abstract: A novel graphene-based gas sensor was fabricated by introducing 4-(hexafluoro-2-hydroxyisopropyl) aniline HFIPA onto graphene by diazonium salt reaction and integrating it into the interdigital electrode. The graft density was characterized by PABA, and through the response curve of neurotoxic agent, mimetic-methyl-methyl-phosphonate (DMMP), the sensitivity of the sensor was detected.Resultsshowed that the successfully fabricated HFIPA functionalized sensor could detect the minimum gas concentration of 312 ppb, and the detection sensitivity and signal-to-noise ratio improved, indicating that it was an excellent gas sensor with great potential.