The insertion reactions of the germylenoid H2GeLiF with the halogenated germane GeH3X (X = F, Cl, Br) were studied using the DFT B3LYP and QCISD methods. The geometries of the stationary points on the potential energy surfaces of the reactions were optimized at the B3LYP/6-311+G(d, p) level of theory. Then the single-point energies were calculated at the QCISD/6-311++G(d, p) level. The calculated results indicated that along the potential energy surface, there are one precursor complex (Q), one three-memberedring transition state (TS), and one intermediate (IM), which connected the reactants and the products. The illustrations of the mechanism of the insertion reactions provided a new reaction mode of germanium-germanium bond formation.