Poly(3-thiopheneacetic acid), PT3AA, was chemically synthesized via an oxidation polymerization and doped with perchloric acid to improve its conductivity. Using P3TAA as the matrix, composites were fabricated with zeolites by dry mixing to be used as an H2 sensor. Zeolite L (L), mordenite (MOR) and beta (BEA) were chosen in our study. The electrical conductivity sensitivity toward H2 was investigated for the effects of zeolite type, zeolite content, cation type, and cation concentration. The negative electrical conductivity response and sensitivity appeared when exposed with H2. The weaker interaction exists between H2 and the polaron or the bipolaron species than the interaction between N2 and active site of Pth_200:1. At 20 %v/v of L, MOR and BEA, the electrical conductivity sensitivity increased with decreasing Al content due to the reduced interaction with H2 and the greater interaction between H2 and the active sites on the polymer chain. The higher electronegativity and smaller ionic radius of Li+ loaded into MOR caused the lowering of electrical conductivity sensitivity relative to thos of Na+ and K+. Na+ was loaded in zeolite L at 0, 10, 20, 30 and 50 mole%, the electrical conductivity sensitivity increased with increasing Na+ content. For the effect of zeolite content, 20 %v/v of MOR has the highest sensitivity values. The reduction of sensitivity values from 20 to 50 %v/v arises from the diminishing active sites available for the interaction between H2 and the polaron or the bipolaron species.