Perihilar cholangiocarcinoma (PHCC) is the most common type of cholangiocarcinoma and poses a serious threat to the life and health of the Chinese population. PHCC is often accompanied by bile stasis, abnormal hepatocyte metabolism within the hepatic lobules, and varying degrees of liver dysfunction. Additionally, systemic organs such as the kidneys and intestines are affected, leading to a higher risk of liver resection surgery for these patients. Currently, clinical methods are unable to accurately assess the regional liver reserve function in such patients, and many issues in assessment strategies remain unclear and unresolved. On the other hand, the strategies and efficacy of promoting hypertrophy of the future liver remnant before liver resection remain controversial. This article addresses these two issues, discussing their definitions, characteristics, and recent progress in detail.