The capacity of FSM-16 to adsorb trimethylamine and the adsorption mechanism were investigated by experiment and simulation. Highly mesoporous FSM-16 was found to have much higher adsorptivity of trimethylamine than silica gel and activated carbon. The adsorption equilibrium of trimethylamine to these adsorbents was described by a Langmuir-type isotherm. At saturation, the amount of trimethylamine adsorbed by FSM-16 and silica gel increased in proportion to their specific surface area, and all the experimental data for these adsorbents were on the same line. The results indicate that the specific surface area of FSM-16 and silica gel is the most important factor regulating their capacity to adsorb trimethylamine. Further, the adsorption equilibrium constant of the Langmuir parameters suggested that silica-based adsorbents with ca. 2.5-2.7 nm pore size are the most suitable for trimethylamine removal. The results obtained by computer simulation were consistent with experimental ones, and suggested that the adsorption mechanism was dominated by hydrogen bonding.