[Objectives]  To determine the relative toxicity of six insecticides to the cotton bollworm Helicoverpa armigera and provide a foundation and reference for the rational use of insecticides in the management of this pest. [Methods]  Using the topical application method, the toxicities of six insecticides; emamectin benzoate, chlorantraniliprole, cyantraniliprole, indoxacarb, chlorfenapyr, and a mixture of emamectin benzoate and indoxacarb (M-EBI), were tested on 3rd instar H. armigera larvae which collected from four wild populations. The effectiveness of emamectin benzoate and chlorantraniliprole against 2nd-5th instar larvae were also compared. [Results]  The relative toxicity of these six insecticides against H. armigera was: chlorantraniliprole > emamectin benzoate > M-EBI > cyantraniliprole > indoxacarb > chlorfenapyr. The sensitivity of H. armigera from the four different populations to same insecticide varied; sensitivity to indoxacarb varied the most, followed by sensitivity to M-EBI, chlorantraniliprole, cyantraniliprole, emamectin benzoate and chlorfenapyr. Emamectin benzoate and chlorantraniliprole were both highly toxic to 2-4 instar larvae but chlorantraniliprole was more toxic to 5th instar larvae than emamectin benzoate. [Conclusion]  Emamectin benzoate and chlorantraniliprole are currently the best choices for controlling H. armigera and chlorantraniliprole is more effective on older larvae than emamectin benzoate.