The Chinese citrus fly,Bactrocera minax（Enderlein）,is one of the most harmful pests for citrus plants, which caused serious damage in recent years in China. In this study, we observed the ovarian development of B.minax under the microscope by measuring ovary length and width, ovarian index, follicle length, and the number of mature eggs. The results indicated that ovarian development of B.minax could be divided into five stages as follows: previtellogenic stage (Ⅰ), vitellogenic deposition stage (Ⅱ), expectant stage of mature eggs (Ⅲ), peak stage of oviposition (Ⅳ), last stage of oviposition (Ⅴ), which lasted for 1-10 days,10-18 days,18-23 days, 23-33 days and 33 days after adult eclosion, respectively. The results could serve as a grading criterion for assessing the sexual maturation in the Chinese citrus fly, and also benefit for the monitoring and control of B.minax in the field.