This study was performed to investigate the potential application of a chitosan (CS) and quinoa polysaccharide (QS) composite aerogel for the adsorption of dyes from water. The properties of the synthesized CSQS composite aerogel were characterized by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), the Brunauer–Emmett–Teller (BET) method, and X-ray photoelectron spectroscopy (XPS). Results showed that the CSQS composite aerogel possesses a porous, loose and flexible structure with a mesoporous nature and high hydrophobicity. Meanwhile, various factors such as the initial concentration, temperature, contact time, and pH have been investigated for evaluation of the optimum adsorption for the removal of Congo red (CR) and methylene blue (MB) in batch sorption experiments, and experimental results showed that the maximum adsorption capacity was found to be 342 mg g⁻¹ for CR and 57.80 mg g⁻¹ for MB under the optimum conditions. The adsorption kinetics of CR and MB on the CSQS composite aerogel were found to be well modeled by pseudo-second-order and pseudo-first-order kinetic models, respectively. In addition, the experimental equilibrium data were represented well by the Langmuir isotherm model. The results in this article demonstrated that the obtained aerogel is suitable for application in drinking water purification. The entire synthesis process of the CSQS aerogel is green and economical without additional need for toxic agents, which allows the process to greatly reduce the discharge of secondary pollution to the environment. The facile, scalable and general strategy presented here can be extended to the preparation of other polysaccharide-based aerogel materials, and has a good prospects for application in the removal of dyes from water.