The method of computational fluid dynamics with RNG κ-ε turbulence model and Eulerian multiphase flow model was used to the simulation of solid-liquid two-phase feed mixer. Distribution of fluid field and volume fraction of solid-phase were analyzed in the stirred tank of horizontal mixer under the effect of agitator blade with different installing space of mixing blades and various lengths of mixing arms. Based on the results, the appropriate structure parameters could be selected and the simulation also provides theoretical basis for the optimizing design.