The computational fluid dynamics method was used to study the pressure drop and velocity distribution differences in different valve body structures under the same operating pressure, and the particle size changes of the single component cellulose of the micronized dietary fiber of different valve body structures were combined to study the influence of flow channel structure on cellulose miniaturization. The results showed that the smaller of the concentration of cellulose aqueous dispersion was, and the better the micronizing effects of single valve treatment were. The concentration of cellulose aqueous dispersion (≤2%) had no obvious influence on the micronizing effect of group valve treatment. The effects of the valve body structure on the miniaturization effects depended on whether a large area and a large flow rate change were formed in the flow channel.