A novel ceramic nanowires of TiO2 and poly(2-acrylamido-2-methylpropane sulfonate) (TiO2 NWs/PAMPS) composite material films coated on quartz crystal microbalance (QCM) was prepared as a low humidity sensor. The 50 wt.% of TiO2 NWs/PAMPS composite material films showed excellent sensitivity (2.63-Delta Hz/Delta ppm(v)) at 31.5 ppm(v)), linearity (R-2=0.9959) and acceptable response time (64s at 34.6ppm(v)). The low humidity sensing mechanism was discussed in terms of surface texture and nanostructured morphology of the composite materials. Moreover, the adsorption dynamic analysis, molecular mechanics calculation (association constant), was used to elucidate the effect of adding 50 wt.% TiO2 NWs into PAMPS in the increased sensitivity of low humidity sensing. (c) 2005 Elsevier B.V All rights reserved.