To study the effect of surface electric charge and NH-4~ adsorption-desorption on sample soils by removed organic matter before and after.Result showed that :(1) Positive charge and permanent charge increased and variable charge decreased after removed organic matter which had a great deal of variable charge and which covered some permanent charge and neutralixed some positive charge.(2)The change of NH-4~ adsorption-desorption was found to be the best fit the change of surface charge.Organic matter could increase the quantity of NH-4~ adsorption-desorption and decrease the energy of NH-4~ combined.