Aphids are major pests of a wide variety of commercially important plants in agriculture,horticulture and forestry.In the present study,we surveyed the population dynamics of aphid species and the dominant natural enemy species in citrus orchards in Hubei Province.The two-year successive survey under field conditions indicated that five species of aphid damaging citrus,including Aphis gossypii,Aphis spiraecola,Toxoptera citricidus,Toxoptera aurantii and Aphis craccivora were found,and among which T. citricidus and A. spiraecola were dominant species.These two dominant species were present throughout the year and peaked in late spring,summer and autumn.The main natural enemies included spider,ladybug,hoverfly,lacewing,parasitoid,and stinkbug etc.Specifically,population increases of spider,ladybug and hoverfly often followed that of the aphids’,indicating strong top-down forces exerted by these natural enemies.