Abstract: The analytical method for IKI-7899 in cotton field has been improved in this experiment. The results obtained from analysis of the sample added with the pesticides showed that the average recovery rates for IKI-7899 in cotton seed, leaf and soils were 88.3%, 83.9% and 85.9%respectively, and the detection limits were 0.005 ppm, 0.005 ppm and 0.0025 ppm respectively. The improved method satisfies the requirements for the dynamic experiments of IKI-7899 residue in cotton field.