Macrophages play a key role in the progression of nonalcoholic fatty liver disease (NAFLD). Liver macrophages are composed of tissue resident macrophages (Kupffer cells) derived from yolk sac and fetal liver and bone-marrow monocytes-derived macrophages, which have heterogeneity of origin. In addition, the activation state of transcriptomic macrophages in vivo presents broad-spectrum changes rather than a traditional simple M1 or M2 polarization, which in turn causes different functional changes. Therefore, in this review, we assessed the evidence for macrophage involvement in NALFD progression from three aspects, macrophage heterogeneity including its origin, polarization and function, the mechanisms of macrophage activation and action, and the potential therapy strategies for NAFLD through targeting macrophages. These studies on NAFLD development will bring forth more novel treatment targets and strategies in clinic.