Abstract: Acting as “the seventh nutrient”, dietary fiber owns excellent biological function and activity, among which SDF shows better performance than IDF. However, the content of SDF in most plant DF is low, which limites the development and application of functional DF products. Therefore, it is imperative to modify DF to increase the SDF content for improving of the physicochemical application properties of DF. Based on the relationship between DF types and its functionality, the necessity of DF modification is clarified first in this paper. By comparing different methods of modifying DF, the feasibility of modifying DF by fermentation technology is confirmed. And then application of fermentation technology in DF modification is introduced in particular from several aspects, i.e. the advantages, modification mechanism, influencing factors of modification of DF by fermentation technology, as well as the applied range of modified DF. Lastly, the development trend of DF modification by fermentation technology is prospected, providing some theoretical references for the future modification and application research of DF.