Hepatocellular carcinoma (HCC) is one of the five most common malignant tumors. According to the latest statistics of the World Health Organization (WHO), the incident and mortality rates of HCC ranks the eighth and third in the world, respectively, which severely affect people’s health. Exosomes are extracellular vesicles with a bilayer of phospholipids, which carry active substances such as proteins and nucleic acids derived from their mother cells. These exosomes greatly facilitate the exchange of substances and information between cells, and coordinate physiological and pathological processes in the body. In recent years, a large number of studies have shown that exosomal proteins play important roles in the tumorigenesis, development, diagnosis and treatment of HCC. Here we review the composition and functions of exosomes and the role of exosomal proteins in HCC.