The aluminum sludge composite gel spheres adsorbent (AS-GEL) was prepared by using aluminum sludge, polyvinyl alcohol, sodium alginate as raw materials and sol-gel, freeze-drying as synthetic technology to adsorb Cr(VI) in the solution. The effects of solution pH, dosage of AS-GEL, initial concentration of Cr(VI) solution, temperature adsorption time, and the coexisting anion concentration on the adsorption of Cr(VI) were explored by static adsorption experiments. The mechanism was analyzed by SEM, FTIR, and XPS. The results showed that, when pH=4, AS-GEL dosage of 1.2 g/L, Cr(VI) initial concentration of 200 mg/L, temperature of 35℃, adsorption time of 120 min and no coexistence of other anions, the maximum adsorption capacity of Cr(VI) on AS-GEL was 73.364 mg/g. The order of coexisting anions is PO43- >NO3->Cl-. The adsorption of Cr(VI) by AS-GEL conformed to Langmuir isotherm adsorption models, Pseudo-first-order and Pseudo-second-order kinetic equations. The main adsorption mechanism is the electrostatic adsorption and reduction of Cr(VI) by the protonated group. Based on 5 adsorption-desorption experiments, the adsorption capacity remained 89.71% of the initial adsorption capacity. AS-GEL has the characteristics of low cost and easy solid-liquid separation, which has the prospect of engineering application.