Removal of acid dyes from aqueous media has been effectively regarded and for this aim various methods have been tested. So in this study a new physical modification of mesoporous silica SBA-15 with PAMAM dendrimer as a new modifier and its application for the removal of Acid Red 266(AR266) from aqueous media has been verified. SBA-15, SBA-15-Cl and SBA-15-PAMAM were synthesized and then were characterized by FTIR.Also, the surface morphology of SBA-15 was recognized by transmission electron microscopy (TEM).Also, the effects of pH, adsorbent dosage, contact time, dye concentration and temperature as five important parameters for effective adsorption of acid dye were studied.Pseudo-first order and pseudo-second order kinetics models were analyzed to characterizing of adsorption rate. The calculated thermodynamic parameters represented the exothermic and spontaneous nature of the adsorption process. The results represented, SBA-15-Den can be applied as an affective Nano adsorbent for removal of acid dye from aqueous media.