Abstract: Soybean insoluble dietary fiber was degraded via ball milling and high pressure microfluidization,respectively,and their structure and physicochemical properties were investigated. The results showed milled cellulose showed dispersed block-shapes with average particle diameter at 28.06 μm,which was 22.83% of untreated samples. However,cellulosic cluster was observed after microfluidization treatment,with average particle diameter at 7.34 μm,which was 5.97% of untreated sample. Additionally,high pressure microfluidization disrupted the crystalline of dietary fiber,further transform β-I type into amorphous crystal structure,which exposed more inter-molecular hydrogen bonds. The relative crystallinity of SIDF decreased from 40.98% to 3.16%. Compared with ball milling,the water and oil holding capacity of soybean dietary fiber were improved significantly by micro fluidic homogenization. The water and oil holding capacity of pressure-treated soybean dietary fiber was 2.96 and 2.48 times that of control,respectively. Moreover,microfibre hydrogel showed higher oscillation stability,tan δ was 20.73% of control. This might be attributed to the strong hydrogen bonding ability of microfibre and the large space potential resistance formed by microfibre winding in morphology.