Investigations of mercury fixation were carried out on the samples of red soils,black soils,yellow brown soils,loessial -suits and cultivated fluviogenic soils collected from different parts of China.The relationship between the content of mercury added to soil and fixed in soil might be eapreased by the following equation:m=acⁿ,where "m" denotes the amount of Hg fixed (μg/lg soil),"c" denotes concentration of added Hg (μg/lg soil);"a" is a constant;"n" is the exponential.We attributed this reaction to chemical fixation rather than biological,because of the greater reaction speed of its fixation.Owing to the capability of mercury fixation in soil,even in the soil severely polluted by the mercury,the content of mercury in upland crops grown on the polluted soil only ranged in a few ppb,much lower than the critical level of present sanitary regulation.But under the waterlogged condition,the fixed mercury of the paddy field is reduced into the available form and the brown rice appears mercury pollution.The fixation and release of mercury in soils were correlated to the types of soil.The factors influenced fixation and release of mercury are to be further studied.