The adsorption of acetochlor and metolachlor on 6 kinds of soils was measured using batch equilibration technique. It was found that adsorption isotherms couldfit Freundlich equation well. According to the analysis of the correlation between K_af(1 /n) and the physical and chemical properties of the soils, organic matter content of soils was the dependent factor in the adsorption.Theresults showed that the adsorption of metolachlor on soils was weaker than that of acetochlor. Hydrogen bonding was found to be the common mechansm in the adsorption of acetochlor and metolachlor.Charge-transfer was the additive mechanism of acetochlor.