The adsorption-desorption behavior of Hg(Ⅱ) in brown soil was studied to find the difference of the behavior with and without organic matter(OM). The results showed that OM has a great influence on the adsorption-desorption of mercury in brown soil. Without OM, brown soil adsorption rate for Hg(Ⅱ) dropped from 95.62%~93.18% to 62.8%~56.70%, desorption rate rose from 2.39%~7.47% to 2.65%~11.23%. Freundlich equation, Langmuir equation, Henry model and Temkin equation can well describe the isothermal adsorption on mercury process in brown soil with and without OM. The matching result of dynamics equation showed, brown soil adsorption-desorption rate for Hg(Ⅱ) was reduced after OM was removed, elovich equation and double constant equation were optimum, it reached highly significant positive correlation(R>0.708).