The first-principle technique has been employed to determine the structure of benzenethiol (BT) molecule, molecular chains, monolayers and the BT/Pt(1 0 0) system. Their potential structures have been proposed. CASTEP calculation shows that molecular chains and monolayer are self-assembly system. At the coverage of 0.50 ML, the stable structure in BT monolayer almost stands upright on Pt(1 0 0) in the hollow site, which is in good agreement with the experiment. At the coverage of 0.33 ML and 0.25 ML, when BT monolayer adsorbed on Pt(1 0 0) three adsorption sites are all stable, and the best one is bridge site. The interaction between S atom and Pt surface is stronger than that between BT molecules in the adsorption system. (C) 2013 Elsevier B.V. All rights reserved.