Quantum chemical calculations have been performed for the substitution reactions of the aluminum chlorogermylenoid H 2 GeClAlCl 2 with HF, H 2 O, NH 3 , HCl, H 2 S, and PH 3 to get more insights into the reactivity of H 2 GeClAlCl 2 . The theoretical calculated results indicated that the substitution reactions of H 2 GeClAlCl 2 with HF, H 2 O, NH 3 , HCl, H 2 S, and PH 3 proceeded in a concerted manner. There were one transition state and one intermediate which connected the reactants and the products along the potential energy surface. The six substitution reactions of H 2 GeClAlCl 2 with HF, H 2 O, NH 3 , HCl, H 2 S, and PH 3 are compared with the addition reaction s of H 2 Ge with these hydrides. And based on the calculated results we concluded that the substitution reactions of H 2 GeClAlCl 2 with these hydrides involve two steps, one is dissociation onto H 2 Ge with AlCl 3 , and the other is the addition reactions of H 2 Ge with HF, H 2 O, NH 3 , HCl, H 2 S, and PH 3 .