[Objectives]  To investigate levels of insecticide resistance in different Plutella xylostella (L.) populations in Hainan Province, and thereby improve both the chemical control of this pest and management of insecticide resistance. [Methods]  Samples of P. xylostella populations from the Haikou and Sanya area were collected between 2011 and 2014 and their resistance to chlorantraniliprole and spinetoram assayed using the leaf-dip bioassay method. [Results]  The results show that the resistance level of the Haikou population to chlorantraniliprole increased from 0.95 to 303.18 fold during 2011-2012, then fell to 61.37 fold in 2013 and to 92.41 fold in 2014. Resistance levels in the Sanya population tended to increase yearly, with the resistance index increasing from 1.16 in 2011 to 44.00 in 2012, to 51.22 in 2013, and to 120.62 in 2014. The resistance levels of Hainan populations of P. xylostella to spinetoram were moderate, the resistance index of the Haikou population increasing from 1.19 in 2012 to 29.35 in 2013, and to 30.25 in 2014, and that of the Sanya population increasing from 4.43 in 2012, to 30.48 in 2013, then to 54.96 in 2014. [Conclusion]  Resistance levels of Hainan populations of P. xylostella to spinetoram and chlorantraniliprole generally tended to increase over time, eventually becoming moderate, or high. Differences in resistance levels between P. xylostella populations in Hainan may be attributed to differences in the environment and local methods of insecticide use. The application of both insecticides should be reduced and more emphasis should be placed on using them in rotation with other insecticides.