The invention discloses a 1,2,3,4,6-O-pentagalloylglucose germanium complex and a preparation method and application thereof. The 1,2,3,4,6-O-pentagalloylglucose germanium complex is formed by complexing of 1,2,3,4,6-O-pentagalloylglucose and germanium ions. The invention further discloses a specific synthesis process and application of the 1,2,3,4,6-O-pentagalloylglucose germanium complex in preparation of lung cancer treatment or prevention medicine. The synthesized compound is novel in structure, and the synthesis process is simple. The compound has good inhibiting effect on human colon cancer cells HCT116, human cervical cancer cells Hela, human pancreatic cancer cells BxPC3, human small cell lung cancer cells A549, human gastric cancer cells SGC7901 and human breast cancer cells MCF7.