The paper studied the adsorption of reactive brilliant red K-2BP by peanut shell and sawdust modified by phosphoric acid.The influence of the important factors such as the mass ratio of modified peanut shells and sawdust, dosage of mixed adsorbent, pH value, reaction temperature and oscillation rate on adsorption effect was systematically examined through static experiment. It also studied the adsorption mechanism.The results showed that the optimal conditions of adsorption are that the mass ratio of modified peanut shells and sawdust is 1∶3.5, the dosage of mixed adsorbent is 0.9 g, the reaction temperature is 328 K, the pH is 14,and the oscillation rate is 120 r/min.The removal efficiency of K-2BP reaches 98.6%.The most impact factor pH. The adsorption process of K-2BP by mixed adsorbent in water accorded with Langmuir mode and fitted well with pseudo second-order model. The maximum amount of theoretical adsorption is 10.83 mg/g.The adsorption process is endothermic and spontaneous.Overall, the adsorption technology of K-2BP by modified peanut shells and sawdust has good application prospect in treatment of pollutant.