Abstract: The etherification modification with peanut shells dietary fiber as raw material, sodium hydroxide as catalyst and chloroacetic acid as etherifying agent as a result of improvement in solubility of dietary fiber from peanut shells were studied. The optimum processing parameters in chemical modification was optimized by single factor and orthogonal test, meanwhile, its quality using scanning electron microscopy and physicochemical properties studies were analysed. The results showed that the optimum conditions for chemical modification were as follows:Na OH concentration 30%, alkaline temperature 30℃, chloroacetic acid concentration 30%, etherification temperature 55℃, the ratio of mass and solution volume 1∶8 (g/m L) . After chemical modification, the structure and physicochemical properties of peanut shells dietary fiber were improved partially and the structure became loose, homogeneous as well as high dispersibility, and the SDF content was 16.8% which had good quality.