It is emergent to develop a green waste water adsorbent with high efficiency. Therefore, a type of low-cost, green and environmentally friendly konjac glucomannan (KGM)-silk fibroin (SF) composite aerogels were compounded via simple chemical grafting and vacuum freeze drying, and a study on its adsorption capacity was also conducted. The characterizations of FT-IR, SEM, XRD and DSC indicate that the modified aerogels show a porous network space structure and there is a strong hydrogen bond effect between the KGM and SF molecules, which improves the density, compressive strength and thermal stability of aerogel materials. The adsorption experiments show that KGM-SF aerogels can effectively adsorb the water pollutants Cr(Ⅲ) with a maximal adsorption capacity of 82 mg·g^-1. In addition, the adsorption isotherm and dynamic model analysis are used to elaborate the adsorption mechanism of KGM-SF aerogels and explain that the composite aerogels can be single molecule chemisorption. KGM-SF aerogels have potential adsorption capacity.