[Aim] Large-scale cultivation of transgenic GM crops may have unwanted ecological effects, triggering the need for environmental safety assessments before commercial release.[Method] Plots of a high-yielding transgenic (RRM2) cotton cultivar and its parental conventional cotton (CCRI12) were systematically surveyed to examine the field population density of the cotton aphid and several natural enemies in 2013 and 2014 in Anhui Province, China.[Result] The type of wingless aphid in transgenic RRM2 cotton increased significantly compared with its non-transgenic parent, cv. CCRI12. Densities of winged Aphis gossypii also increases, but the difference was not significant. The population densities of several predators was no significantly different between these two cultivars.[Conclusion] The studied transgenic cotton cultivar supported more cotton aphids than its parental isoline, but this was not followed by an increase in the field population density of predators. This study could contribute to the assessment of environment safety of the new GM cotton.