Abstract: The soil Chorsulfuron residue bioassaymethod is described in the article. The relative model has beenestablished between the chlorsulfuron concentration(Y)andthe Iength of corn root(X):Y=30.562-36.38 InX+14.828(InX)²+2.043(InX)³. The models is suited to determine thesoil Chorsulfuron residue concentration from 0.1 to 4.0 μg/kg. The minimum detection for Chlorsulfuron is 0.1μg/kg.