Biennial sweet clover (Melilotus.albus Dear) is the main green manure crop in Jilin Province.The nodulation and nitrogen fixation activity of nodules of biennial sweet clover in different soils were investgeted during 1979-1980.Nodulation arrd nitrogen fixation activity (A.R.A) were found in all plants and nodules of the sweet clover in field,but their differences were greater between different soils.The fresh weight of nodule was highest in meadow black soil (about 3g per soil core),and it was getting decreased from warped soil,podzolic soil,black soil,to salt-affected soil in which it is lowest (less than 0.1g per soil mre).