The mixing mechanism of a punched agitator used in solid-liquid suspension system was studied basing on the enstrophy and energy dissipation of the vortex theory. The effects of the configuration parameters on stirring performance were discussed. The results show that efflux from such punched agitator with simple structure can not only strengthen vortex diffusion, but also reduce the power consumption by diminishing the projection area in the direction which the paddles round. Obviously, this is beneficial to lower critical suspension velocity and promote mixing efficiency in stirring tank. It is indicated that the punched agitator owning quite broad application prospects.