Phosphine(PH3) is very effective fumigant and is widely used to control pests. Oxygen treatment was found to enhance phosphine toxicity and reduce fumigation time. We researched the insecticidal activities and synergistic effects of oxygen with phosphine(PH3) against on adult stage of 6 agricultural pests as Frankliniella occidentalis, F. intonsa, Pseudococcus comstocki, Planococcus citri, Myzus persicae and Tetranychus urticae. Adults F. occidentalis, F. intonsa, P. comstocki and P. citri was highly susceptible to PH3 at 2mg/L for 2h treatment. However, M. persicae and T. urticae were showed very low fumigation effects at 2mg/L for 2h treatment. These 2 pests were treated with PH3 to increase the times (16h and 20h). And we also researched the synergistic effects of PH3 under controlled atmospheres of 50% and 80% oxygen(O2). Increase of the time and atmospheric oxygen showed improving activities of the PH3 in the 2 agricultural pests. Therefore, PH3 is an effective fumigant against F. occidentalis, F. intonsa, P. comstocki and P. citri, and its synergistic effect with oxygen is effective to control M. persicae and T. urticae. PH3 with oxygen could be useful for managing the agricultural and quarantine pests.