The liver is an important organ in the human body responsible for many key physiological processes, including metabolism, detoxification, and immunity. Normally, homeostasis of macrophages in the liver maintains liver function. Disruption of macrophage homeostasis, evolution among different cell subsets, and altered function contribute to the progression of non-alcoholic fatty liver diseases (NAFLD). Single cell RNA-seq technology is used to identify specific macrophage subsets for the treatment of non-alcoholic fatty liver diseases. This article will review the classification, heterogeneity, and role of hepatic macrophages in non-alcoholic fatty liver diseases.