Abstract: 【Objective】 To explore the effects of plant essential oils on the behavior of the melon flies Zeugodacus cucurbitae （Coquillett）， screen out single essential oils with repellency effect and binary mixtures with synergistic effects， which could provide theoretical basis and technical support for the development of novel green repellents against melon flies based on plant essential oils. 【Method】 A selective oviposition repellency bioassay was used for preliminary scree-ning of 12 commercial essential oils， and a Y-tube olfactometer choice test was further employed to evaluate the effects of candidate oils on the behavior of melon flies. The selected highly effective essential oils were mixed in different ratios to form binary combinations， and their repellency effects were again assessed by the selective oviposition repellency bioassay and the Y-tube olfactometer test. 【Result】 At a concentration of 10.0 mg/mL， camphor essential oil， artemisia essential oil， and thyme essential oil exhibited significant oviposition repellent effect against melon flies （P<0.05， the same below）， with repellency rates of 58.02%， 53.34%， and 60.14% respectively. In the Y-tube olfactometer tests， at three concentrations （0.1， 1.0， and 10.0 mg/mL）， the response rates of both female and male melon flies to camphor essential oil， artemisia essential oil， and thyme essential oil were all above 70.00%. Camphor essential oil and artemisia essential oil showed repellency effects on both females and males， whereas thyme essential oil only repelled males. When camphor essential oil and thyme essential oil were mixed at a mass ratio of 4∶6， artemisia essential oil and thyme essential oil at 4∶6， and camphor essential oil and thyme essential oil at 2∶8， all three binary mixtures exhibited synergistic effects， with synergism ratios of 1.47， 1.52， and 1.32， and oviposition repellency rates of 87.22%， 86.65%， and 79.03% respectively. In the Y-tube olfactometer tests， the response rates of both female and male melon flies to the above three mixed oils were all above 70.00%， and all three mixtures showed repellency activity against both sexes. 【Conclusion】 Camphor essential oil， artemisia essential oil， and thyme essential oil all possess highly repellent effect against melon flies. Their binary mixtures， which were camphor-thyme （4∶6）， camphor-thyme （2∶8）， and artemisia-thyme （4∶6）， all exhibit synergistic repellency effects and have potential for development as repellents against melon flies.