[Objectives]  To determine the toxicity of spinetoram and ethiprole to Frankliniella occidentalis, and the effect of these pesticides on detoxification enzymes and acetylcholinesterase activity. [Methods]  The effects of sublethal concentrations (LC₂₅) of spinetoram and ethiprole on 2nd instar nymphs of F. occidentalis were measured using the leaf dipping method. Changes in carboxylesterase (CarE), glutathione S-transferase (GSTs), cytochromeP450 (P450), multi-function oxidase (MFO) and acetylcholin esterase (AChE) activity were measured 12, 24, 48 and 72 hours, after insects had been treated with LC₂₅ doses of spinetoram and ethiprole. [Results]  F. occidentalis was sensitive to both spinetoram and ethiprole and the sublethal LC₂₅ concentrations of these pesticides were 0.7089 mg/L and 0.0033 mg/L, respectively. CarE, GSTs, MFOs and P450 activity increased significantly after treatment with an LC₂₅ dose of spinetoram. AChE activity decreased from 12 to 48 hours after treatment, falling to the level of the control group by 72 hours after treatment. After ethiprole treatment, CarE and P450 activity increased significantly but GSTs activity didn’t change significantly, compared to the control. MFOs activity didn’t differ significantly from that of the control after 12 and 24 hours, but was higher than the control 48 and 72 hours after treatment. AChE decreased significantly throughout the experimental period. [Conclusion]  Sublethal concentrations of spinetoram and ethiprole affected the activities of detoxification enzymes and acetylcholin esterase in F. occidentalis to different degrees after different periods of time post-treatment.