[Objectives]  To investigate the relationship between resistance to chlorantraniliprole and efficacy control of Plutella xylostella (L.). [Methods]  The susceptibility of P. xylostella larvae to chlorantraniliprole, and the control efficacy of this insecticide, were evaluated in the field. [Results]  The control efficacy of chlorantraniliprole on P. xylostella fell gradually from 97.74% in 2011 to 63.53% in 2015, and the relative toxicity ratio increased from 1 in 2011 to 11.93 in 2015. [Conclusion]  These results indicate that resistance and control efficacy are generally inversely correlated.