From first-principles calculations, we calculated the crystal structure, electronic properties, and phonon properties of SiH4(H2)2 and LiSiH4(H2)2 at 180 GPa, respectively. The electronic properties of SiH4(H2)2 and LiSiH4(H2)2 were studied by analyzing the band structure, density of states (DOS), charge density and Mulliken population. The results show that both substances are metals. However, the lower N(Ef) of SiH4(H2)2 indicates that the Cc structure behaves in a weak metal nature at 180 GPa. Moreover, after Li atom doping, significantly improved the H atoms near the Fermi surface states density (from 0.04 to 0.34 states/eV). And when the pressure reaches 350 GPa, the DOS of H is as high as 1.02 states/eV. This leads to a higher Tc. And the analysis of phonon dispersion and phonon state density (PDOS) shows that the dynamic stability of LiSiH4(H2)2 is better. By comparing the electronic and phonon properties of SiH4(H2)2 and LiSiH4(H2)2, we can find that the superconductivity of SiH4(H2)2 can be improved by doping Li atoms to a certain extent.