Abstract: Abstract：【Objective】The text was mainly to find the microorganism to degrade aflatoxin B1 and realized the application of biological degradation on AFB1．【Method】Using cumarin as the carbon source and energy，ten strains were first screened out of 1500，and the strain NMO-3 had high growth speed，its Morphology colony was big，the ability of utilizing cumarin was strong．We use aflatoxin B1 to have the second screening，through the ELISA method detecting AFB1 degradation ratio．【Results】The strain NMO-3 was screened out of ten strains， the degradation ratio of AFB1 reached 85．7%，it was prominent to the others（p﹤0．01）．With the analysis of colony morphology，physiological and biochemistry experiments，and 16SrDNA gene sequence，the strain NMO-3 was identified as Stenotrophomnas sp．【Conclusion】The results of this text showed that using cumarin as the carbon source and energy to screen out the AFB1 degradation strains was feasible．The text firstly reported the strain’s detoxification function．