Abstract: In order to scientifically evaluate the effect of Mieyiwei baits in controlling the Solenopsis invicta, S. invicta mounds were treated with 0.45% Tetramethrin + 0.05% Cypermethrin in the field. The suitable control period in Kunming and control effect on 3 size type mounds were studied. The results showed that there was a significant difference in the worker population of S. invicta before and after the application. In June, July and August, the control effect of worker and active mounds were the best, the work control effect was more than 99% and the active mounds control effect was more than 75%. Followed by April, May and September. The control effect in January, February, March, October, November and December was poor, the control effect of worker was lower than 90%, and the control effect of active mounds was lower than 55%. The control effect of active mounds was significantly different after 10, 20 and 30 days of application. The results of this study showed that there are some differences in the control effect in different months, the suitable control period of S. invicta in Kunming was April to September and best defense after 30 days.