Abstract: The efficiency of cyantraniliprole on Plutella xylostella was studied, and the residue dissipation dynamics of cyantraniliprole in Brassica oleracea was analyzed. According to the research result, a safe application method of this insecticide was developed to provide a guideline for the application of cyantraniliprole in the field. Field trials by different doses indicated that 10% cyantraniliprole OD at the available dosage of 21 g/hm2 had good control effect (92.8%-98.3%) from 24 h to 7 d after the application of the pesticide. The results of residue tests showed that the half-life of cyantraniliprole in B. oleracea was 3.86 d when the 10% cyantraniliprole OD was applied once at double recommended dosages (42 g a.i./hm2). The residue risk in the harvested B. oleracea was positively correlated with application dose and spraying frequencies. The safety interval was suggested to be 3 d in the open field if the recommended dosages (21 g a.i./hm2) was applied no more than 2 times.