In this work, a high-performance sensor capable of effectively detecting nerve gas, a type of chemical warfare agent (CWA), was realized by conductive paper with polyaniline (PANI) nanofiber and graphene sheet. Improvements in electrical properties and sensor performance of conductive papers were realized by the addition of optimized amounts of graphene and PEO. Conductive patterns containing PANI nanofiber/graphene cofillers were fabricated into sensor electrodes of various sizes and shapes by screen printing. The prepared conductive papers were exposed under DMMP at various concentrations of at least 3 to at most 30000 ppb.