Abstract: Double network composite beads (MCC-SA-SEP) were synthesized by a floating droplet method, in which microcrystalline cellulose (MCC) and sodium alginate (SA) worked as the network frameworks, and sepiolite (SEP) was a functional component. The microstructure and thermal properties of the as-prepared MCC-SA-SEP beads were characterized by SEM and TG, respectively, and the adsorption performance for methylene blue (MB) aqueous solution was studied. The results present that the MCC-SA-SEP beads have three-dimensional porous structures, and the thermal stability increases gradually with the increasing of SEP contents. The adsorption process of MCC-SA-SEP follows the pseudo-second-order kinetic model and Langmuir isotherm, with the maximum adsorption capacity of 333.3 mg/g for MB. After five regeneration cycles, the adsorption capacity could still retain 85.4% of the initial adsorption amount, demonstrating a novel organic-inorganic hybrid adsorbent for dye waste water treatment.