The micronization of plant particles usually transfers substantial insoluble fraction into soluble elements, resulting in a soluble-insoluble binary system and the content of soluble elements can not be neglected. The present work aims to investigate the interaction between soluble elements and insoluble particles obtained from sugar beet pulp by microwave heating with ultrasonication, and their contribution to the synergistic emulsification performance. The soluble elements (∼40%) (sugar beet pectic substance, SBPS) and insoluble fibrous particles (IFPs) were separated from micronized sugar beet pulp (MSBP). Quartz crystal microbalance with dissipation analysis revealed that SBPS could irreversibly adsorb onto IFPs with an adsorbed mass of 32.2 μg/mg Fiber. By adopting sequential extraction and specific enzymatic hydrolysis for the modification of IFPs and SBPS, it was found that their non-saccharide fraction played an important role in the interaction. Larger molecular weight subfractions with abundant protein and ferulic acid content were the main adsorbable fraction in SBPS, and the interaction was driven by hydrophobic interaction. The soluble-insoluble binary system promoted the interfacial adsorption of both IFPs (from 65.6% to 82.2%) and SBPS (from 9.6% to 19.6%), forming a hybrid interfacial coverage (with SBPS-coated IFPs and SBPS) and endowing emulsion with better stability. These findings provided a guideline for understanding the emulsification mechanism of plant particles.