The insecticidal activity of 2% Celangulin E.C against some populations of Tetranychus cinnabarinus, including a susceptible strain (SS), a fenpropathrin-resistant strain (FeR) and an abamectin-resistant strain (AbR), was studied. Laboratory bioassays indicated that the toxicity of celangulin against the SS strain was highest, its LC₅₀ being 1.3883mg/L, compared with pyridaben (53.8446mg/L) and omethoate (116.0337mg/L), and the toxicity of celangulin against FeR (LC₅₀=1.3825mg/L) was almost the same as that of the SS strain, i.e. there was no cross resistance between celangulin and fenpropathrin. But the toxicity of celangulin against AbR (LC₅₀=6.9203mg/L) was inferior to that against SS, and its LC₅₀ value increased 4.98-fold, which showed that some cross resistance existed between celangulin and abamectin. The effect of celangulin E.C against T. cinnabarinus was higher than pyridaben and omethoate in a potted plant experiment. The dose of the celangulin's active ingredient that was needed to obtain 95% mite mortality was 1/40 of pyridaben and 1/60 of omethoate. In addition, carboxylesterase (CarE) activity inhibited by celangulin was correlated with the action mechanism of celangulin on T. cinnabarinus. Celangulin can therefore be used to control T. cinnabarinus, which harms vegetables, cotton and other agricultural crops.