The growth characteristics of transgenic cotton and its effects on the insect communities in cotton fields, which is a key aspect of the evaluation of the environmental safety of transgenic cotton, must be assessed. In this study, we selected the new transgenic ACO2 cotton and its parental CCRI 24 as samples to test cotton growth and changes in insect community in the city of Anyang in Henan province in 2013 and 2014. The results showed that, the leaf dry weight was not significantly different between transgenic cotton and the parental cotton plant at the seeding, bud, flowering or boll stages. In the seedling and bud stage, the leaf area and leaf area ratio of transgenic cotton was not clearly different from the parent. However, in the flowering and boll stage, the ratios were significantly different from those of the parents, specifically 27.1% and 26.2% higher in 2013, and 16% and 19.9% higher in 2014, respectively. There were no significant differences between the transgenic cotton and its parent plant with respect to plant height, leaf number, boll number, bell number or boll abscission number. However, boll branch number in transgenic plants was significantly higher in the parents at the boll stage. During the three adult peaks of occurrence of Helicoverpa armigera, the corrected mortality of cotton bollworm and beet armyworm in transgenic cotton was much lower but was not significantly different from the parental control. The total number of individuals comprising the insect, pest sub, and natural enemy sub communities in the transgenic cotton field were higher than that in parent cotton field, at 11.5%, 10.5%, 33.4% and 8.1%, 63.1%, 12% in 2013 and 2014, respectively, with a significant difference in 2013. Owing to the diminished occurrence of insects in 2014, the difference was not significant. However, the order, family, and species as well the indices for biodiversity, evenness, and dominant species were not significantly different. The above results demonstrated that no obvious advantage was apparent in the new transgenic cotton in respect to growth potential after the ACO2 gene was imported into the cotton. However, the yield component traits in some periods were enhanced. This preliminary study illuminates the rules and dynamics and competition of insect communities as well as the survival of transgenic cotton plants in the field. This could provide a theoretical basis for the evaluation of new transgenic cotton and environmental safety, and this could be the beginning of the accumulation of data concerning both these topics.