Abstract Density functional theory (DFT), as a theory to explore the electron microscopic structure of materials, guides and promotes the rapid development of the perovskite field. In the context of the global energy revolution, “green”, “safe”, and “sustainable” have become the keywords in the field of perovskite research. Because of its abundant reserves on the earth, less harm to the environment and human health, strong stability, and other advantages, germanium has been widely concerned in the field of perovskite solar cells (PSCs). In this study, the differential charge densities, the total densities of states (TDOS), the partial densities of states (PDOS), and the thermodynamic properties of four AGeX3 germanium-based perovskite materials are calculated by using Materials Studio (MS). It is found that Ge atomic orbital electrons play a crucial role in the absorption of photon energy and the generation of photocurrent. The PSCs of the AGeX3 structure will perform better. This study contributes to the realization of efficient germanium-based PSCs in experiments, provides a broad prospect for researchers in this field, and plays a vital role in the future research of germanium-based perovskite.