N-heterocyclic carbene ligands have attracted extensive attention, because of their excellent catalytic performance. A number of anionic N-heterocyclic carbenes and their metal complexes were successfully obtained, via introducing a variety of anionic functional groups into the N-heterocyclic carbene side arms. Anionic N-heterocyclic carbenes and their metal complexes covered almost all transition metals, and exhibited good catalytic performance in organic catalysis and olefin polymerization. According to the recent research reports, the synthesis and application of C-anionic, N-anionic, O-anionic, S-anionic N-heterocyclic carbenes and their metal complexes were reviewed. The development trends of anionic N-heterocyclic carbene were proposed, on the basis.