Abstract: Compared with the citrus sinensis osbeck peel residue adsorbent,the adsorption ability for crystal violet and methylene blue was studied after modified by microwave and phosphoric acid. Effects of adsorption time,pH value,adsorbent dosage,initial concentration of dyestuff,and adsorption temperature of adsorbent on absorption ability were determined. The properties of absorbent were characterized by SEM and IR. The results showed that,when the pH was 7,0.1 g adsorbent was added into 50 mg·L^-1crystal violet solution and 100 mg·L^-1 methylene blue solution adsorb for 1.5 h,resepectively. The removal rate for crystal violet increased from 66.5%(before modification)to 99.4% in 30 ℃,and the removal rate for methylene blue increased from 57.1%(before modification)to 96.3% in 40 ℃. Adsorption of modified citrus sinensis osbeck peel residue to crystal violet was in accordance with Langmuir Isothermal model,and the adsorption to methylene blue was in accord with Langmuir and Freundlich isothermal adsorption model. The adsorption kinetics was in accord with pseudo second-order kinetic model. The results indicated that absorption ability of the modified absorbent was better than the unmodified absorbent