The objective was to study the effects of biological dissociation and dynamic high pressure microfluidization (DHPM) on composition, physical and chemical properties and functional characteristics of soybean dietary fiber. The results showed that DHPM produced an increase of soluble dietary fiber (SDF) and a decrease of insoluble dietary fiber (IDF), and raised the IDF/SDF ration to 1.87;in addition, by comparing the contents of the remaining components of the biodissociated soybean dietary fiber with different treatment pressures, it was found that DHPM had no significant effect on the water content of the biodissected dietary fiber (P>0.05). DHPM also modified hydration propeities and oil holding capacity greatly, but it did not affect cation exchange capacity significantly;under the condition with pH value of 7, the difference of the adsorption capacity of heavy metal in dietary fiber with different pressures was not significant, and the adsorption effect of dietary fiber on the same heavy metal ion at pH value of 7 was higher than that at pH value of 2. The absorption of glucose by dietary fiber was increased with the increase of treatment pressure, and it was decreased slightly at 200MPa. The glucose absorption capacity of dietary fiber treated with different pressures was increased with the increase of glucose concentration;the highest α-amylase inhibitory capacity was 18.42% from dietary fiber, which was increased by approximately 36%, 32%, 28% and 27%, respectively, in dietary fiber samples treated from 0MPa to 150MPa. The sample showed a higher bile acid binding capacity. Therefore, DHPM could be considered as good methods to improve the functionality of dietary fiber in soybean.