The fenugreek gum modified by maleic anhydride was synthesized with fenugreek gum (FG) as material ,using maleic anhydride (MAH) as the esterification reagent and N-bromobutanimide as catalyst. The optimum reaction condition of MAFG was obtained as follows: MAH and FG in mass ratio 0.35:1, 60℃ reaction temperature, 4 hours reaction time. The structure of MAFG was characterized by means of FT-IR, XRD, meanwhile, the rheological property of the aqueous solution and the gel of MAFG were discussed. The results showed that the modification can reduce the crystallinity. Compared to FG, MAFG has better thickening property. The rheological property of the gel of MAFG was better than FG. The gel of MAFG has good temperature and shear stability properties.