Abstract: In this experiment, Forsythia suspensa was used as raw material to extract insoluble dietary fiber (IDF) by double enzyme method, and then the extracted IDF was chemically modified by carboxymethylation (CM), hydroxypropylation (HP) and cross-linking (CL), and their physicochemical properties, structure and emulsifying properties were analyzed. The results showed that the modified treatment reduced the water holding capacity of Forsythia suspensa IDF and significantly increased the oil holding capacity by 21%~53.0% (P<0.05). The CM and HP modification increased the expansion capacity of Forsythia suspensa IDF by about 73%. The structural characterization showed that the three modification treatments significantly reduced the particle volume, looser structure, improved the thermal stability and reduced the crystallinity of Forsythia suspensa IDF. The modification of Forsythia suspense IDF emulsion had different degrees of improvement in temperature, pH and ionic strength stability, and had good storage stability. The Forsythia suspensa IDF emulsion stability was the best after adding CL modified Forsythia suspensa IDF.