Sepiolite/poly (sodium acrylate-acrylamide) composite was synthesized by using inverse suspending polymerization method under different dispersant content, neutralization degree and ratio of monomer with orthogonal experiments. The surface morphology, structure and humidity controlling properties of composite were observed and determined. The results show that sepiolite/ poly (sodium acrylate-acrylamide) composite is in a fine particle with rough surface. During the polymerization process, acrylate and acrylamide monomer is grafted with hydroxyl on the surface of sepiolite and then intercalated successfully into the silica layers of sepiolite. The impact of three factors on the humidity controlling behavior of composites increases by the order of dispersant content, ratio of monomer and neutralization degree. The optimum preparation parameters are dispersant content of 10%, neutralization degree of 85% and ratio of monomer 2:1.