Polyaniline composite was prepared with chemical oxide method by adding a small amount of TiO2 sol-gel. This film on the interdigital electrodes of carbon paste was formed via spin-coating or immersion method with in situ polymerization approach. And its gas-sensitivity to trimethylamine was examined at room temperature. The results indicated that, the heat stability of polyaniline film was improved obviously by adding 10 wt% TiO2. Meanwhile, this film still showed excellent gas-sensitivity to trimethylamine of 5.14 x 10(-7) mol mL(-1), its value of gas-sensitivity was up to three to five orders of magnitude within 3 min, and had good selectivity to analogy gases. The film also exhibited good reproducibility and stability, and easily recovered with high-purity N-2 at room temperature. (c) 2005 Elsevier B.V. All rights reserved.