The chemically modified cellulose Triaminoguanyl-modified (TAGu-MC)  was synthesized and fully characterized by using  a variety of suitable techniques, including scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and elemental analysis. The synthsized (TAGu-MC) was applied for  acid dye uptake from aqueous dye solutions, including 2-(4-Sulfo phenyl azo)-1,8-dihydroxy-3,6 naphthalene disulfonic acid trisodium salt (SPADNS). Significant variables such as pH effect, temperature effect, the intial concentration, the contact time were investigated to confirm the ideal adsorption conditions. The outcomes demonstrate that cellulose fiber cationization is a powerful and promising strategy for improving the adsorption of acid dyes was adsorption capacity 140 (mg/g).