As a novel type of post-translational modification, protein lactylation has captivated extensive attention in the field of tumor biology in recent years. Hepatobiliary and pancreatic tumors are a type of malignant tumors in the digestive system with high incidence and poor prognosis. The complicated mechanism of incidence and development remains to be urgently unraveled. By regulating the metabolic reprogramming of tumor cells, promoting cell proliferation and mediating immune escape, protein lactylation has gradually become an important breakthrough point to understand the biological characteristics of hepatobiliary and pancreatic tumors. In this article, the molecular mechanism and detection methods of protein lactylation were systematically reviewed. The functional role and the potential of clinical application in hepatobiliary and pancreatic tumors were highlighted. Combined with the latest research progress, the challenges and future development trends in this field were illustrated, aiming to provide theoretical basis and novel ideas for optimizing basic research and clinical treatment strategies.