The method of configurational-bias Monte Carlo simulation is used for investigating the adsorption and distributions of ethanethiol in MFI and MOR type zeolites. The calculated adsorption quantity of ethanethiol in MFI is close agreement with the experimental data by means of IR spectroscopy and thermogravimetry. The calculated results show the adsorption quantity of ethanethiol in MFI is much more than that in MOR under coequal conditions. The observation of distribution of MFI is attributed to preferential adsorption of the ethanethiol molecules in the straight and zig-zag channels. In the intersection of straight channels and zig-zag channels, it accommodates the ethanethiol molecules like a reservoir. The straight channels for MOR accommodate all ethanethiol molecules almost, however, in the other channels, the ethanethiol molecules cannot be found. (C) 2004 American Institute of Physics.