The work aims to prepare a novel soy protein isolate-konjac gum composite with excellent hydrationresistance and low viscosity. Soy protein isolate (SPI) and soluble dietary fiber konjac gum (KGM) were used as the main raw materials. The SPI was heat-induced for aggregationand the KGM was treated throughacid-base modification. The resulting SPI-KGM composite was cross-linked by transglutaminase coupled with glycosylation reaction to produce a hydration-resistant SPI-KGM composite. Compared with the apparent viscosity of the control (untreated mixture of SPI and KGM), the viscosity of the natural KGM reaction composite, acid-modified KGM reaction composite and base-modified KGM reaction composite decreased by 53.25%, 82.68%, and 77.94%, respectively, after room temperature reconstitution.After high-temperature reconstitution at 100 ℃, the viscosity decreased by 59.55%, 88.35%, and 87.22%, respectively. The heat-modified SPI and acid-base modified KGM react to form a composite. Compared with the natural untreated composite, the viscosity of the composite system significantly decreases, effectively improving the low viscosity and swallowability after reconstitution, and has good water absorption and stable viscosity in the stomach digestive system, providing a theoretical basis for developing high-protein and high-fiber food products.