The potassium tin sulfied (KSnS) was prepared by hydrothermal method using potassium carbonate, tin powder and sulfur powder as raw materials. The morphology and structure of KSnS were performed by SEM, XPS and XRD. The effects of contact time, pH, coexisting ions, initial cobalt concentration on the adsorption of Co2 by KSnS were investigated via batch experiments. The results show that cobalt sorption of KSnS can reach equilibrium time after about 25 min, and the saturated adsorption capacities is 149 mg/g. When initial concentration of cobalt is 5mg/L and V/m=2500mL/g, the distribution coefficient of KSnS to Co2 can reach 6.3?105mL/g and the removal rate is 99.84%. When the solution is neutral, KSnS has the best adsorption performance. KSnS has high selectivity to Co2 , and high concentration of coexisting ions (K , Na , Ca2 , Mg2 ) has little effect on the removal rate of Co2 . The sorption kinetics of KSnS for Co2 can be described by pseudo-second-order kinetic equations, and the adsorption process is mainly chemical adsorption. According to Weber-Morris model and Boyd model, the liquid film diffusion process dominates the adsorption rate.