As the largest internal organ of the human body, the liver has an extremely complex vascular network and multiple types of immune cells. It plays an important role in blood circulation, material metabolism, and immune response. Optical imaging is an effective tool for studying fine vascular structure and immunocyte distribution of the liver. Here, we provide an overview of the structure and composition of liver vessels, the three-dimensional (3D) imaging of the liver, and the spatial distribution and immune function of various cell components of the liver. Especially, we emphasize the 3D imaging methods for visualizing fine structure in the liver. Finally, we summarize and prospect the development of 3D imaging of liver vessels and immune cells.