The utilization of volcanic ash and shrimp shell waste into composite material is very interesting to discuss as a strategy to make naturally available materials into valuable, stable and low cost adsorbent. The study is aimed to fabricate the silicabased chitosan biocomposite material from volcanic ash of Sinabung mountain and shrimp husk by sol gel method to be used as an adsorbent. The procedure is performed by converting volcanic ash into silica salt, extracting the chitosan from shrimp skeleton, and the synthesis of the silica-chitosan biocomposite by mixing the silica with chitosan in the aid of bifunctional glutaraldehyde cross-linking agent. The silica-based chitosan composite is successfully prepared from the mixture of 20 mL 58% (v/v) Na2SiO3 with 2% (w/v) chitosan to obtain biocomposite material (SChC1). A rapid and simple method to bind the silica with chitosan is achieved. The resulting biocomposite is amorphous, in the form of small crystals, a rough surface with a large pore area between 2 theta = 20-24 degrees. Adsorption capacity of the biocomposite material has been evaluated, where it has the capability to bind cadmium ion due to the presence of amine group in the material surface. The prepared material of silica-chitosan biocomposite has the potential to be used as an adsorbent.