Abstract: Floating harmful substance has been affecting people's daily production. Rotary jet generate equipment has an effective control on the spreading of floating harmful substance, such as dust, harmful gas and so on, especially on the close-distance pollution sources. Based on the theory of fluid mechanics, the numerical simulation for the suction flow field controlled by rotary jet generate equipment was made, and a numerical method was established. Then a grid division was carried out and analysis of the boundary conditions. Computational fluid dynamics software was used for the simulated calculation of this suction flow field. Results show that when the flow ratio is about 0.6, formation of the cyclone is stable. Meanwhile, suction effect control of different size of dust particles is better also. The calculation results agree with the experimental results, and provide a theoretical basis for the improvement of rotary jet generate equipment.