In view of the shortage of water resources in China, the question of low solubility of water-soluble fertilizers, and the uniformity of water-fertilizer mixing in fertigation, an efficient dynamic fertilizer mixer was designed, and the mixing device of the fertilizer device was simulated by using ANSYS simulation software. The mode and stress strain simulation analysis of the mixer was carried out. At the same time, based on Fluent module, the flow field and velocity field of mixing process of the fertilizer mixer were simulated and analyzed. The results showed that the safety factor was 11.95, the lowest order modal main frequency was 19.13Hz, and each frequency was much larger than the frequency of excitation source of mixed fertilizer. It showed good vibration characteristics and fully met the industrial design requirements. In addition, the distribution diagram of the flow field of different stirring speeds was analyzed. The velocity vector distribution of the mixer was more complex in the rotating stirring process under the rotating speed of the critical agitation speed. It was easy to produce more spoiler and turbulence in the mixer, and can effectively improve the effect of mixing. Meanwhile, the increase of stirringspeed had little effect on the flow field distribution inside the mixer. Finally, the best stirring speed was 600r/min, which reduced the energy consumption while achieving good mixing effect.