Abstract: Cyantraniliprole is the newest commercial insecticide from the anthranilic diamides. In the present work,the baseline susceptibility to cyantraniliprole for Plutella xylostella was surveyed from a susceptible strain (Roth) and four geographical populations sampled from Guangdong province, China, and the median lethal concentrations (LC50) were assayed by using the pesticide-membrane method. The sensitivity baseline of P. xylostella to cyantraniliprole was 0.54 mg/L,and the LC50s of the Cencun, Huizhou and Shijing population from Guangdong province to cyantraniliprole were 10.64, 37.72, 21.92 mg/L, respectively, which were 19.55- to 69.85- fold higher than the LC50 of Roth. The LC50 of the three populations to chlorantraniliprole was 71.1, 63.73, 40.82 mg/L, respectively. However, the Lianzhou field population remains susceptibility to cyantraniliprole, LC50 was 0.23 mg/L. The result showed that middle level of resistance to cyantraniliprole had evolved in field populations from Guangdong province of Southern China, and the developing trend was consistent with chlorantraniliprole, so the farmers should be careful to use this insecticide.