It is very necessary to quickly and selectively detect the abused drugs in real time, because of their bad influence on the central nervous system. So ZnO nanorod bundles were prepared by simple hydrothermal reaction combined with calcination in this paper, which were assembled into thick film gas sensor to detect three analogs of drugs. Such ZnO nanorod bundles gas sensor exhibited not only good gas response and selectivity, but also good reproducibility and stability to the saturated vapors of three kinds of drugs (C10H15NO, C9H13NO, C8H9NO2) at 252 degrees C. The excellent gas response can be ascribed to its rough surface and the large number of holes formed by nanorod bundles accumulation, which are conducive to diffusion, adsorption and desorption of gas molecules on ZnO nanorods. The reaction mechanism was further analyzed and discussed by XPS.