Abstract: To effectively prevent the attack of aphids on Chrysanthemum morifolium, safety tests and field efficacy trials were carried out to optimize the application technique of 70% imidacloprid water dispersible granule (WDG) for controlling aphids. The results of laboratory safety test showed that 70% imidacloprid WDG was safe to different Chrysanthemum morifolium varieties including‘Jinju II’ ,‘Xiao Huangju’ ,‘Zao Xiaoyangju’ ,‘Yizhongdabaiju’ ,‘Futian Baiju’ , etc. The field efficacy trials in Zhejiang and Hubei Provinces indicated that 70% imidacloprid WDG had rapid and persistent control effects on aphids such as Macrosiphoniella sanborni, Myzus persicae and Aphis gossypii. The correction efficacies were above 70%, 85%, 90% and 80% after spraying 52.5 g a.i./hm2 for 1 day, 3 days, 7 days and 14 days, respectively. And no influence was observed on Chrysanthemum morifolium and non-target organisms. The results supported that 70% imidacloprid WDG was suitable to register and use widely for controlling aphids on Chrysanthemum morifolium.