Because N-heterocyclic carbene ligands exhibit similar characteristics to phosphine ligands, they have been widely investigated. NHC metal complexes are highly active in catalyzing coupling reactions. The main reason is the easy synthesis of the ligands and their metal complexes, comprising the stability of the complexes toward moisture, heat or air. In this article, we present a brief introduction to design N-heterocyclic carbene palladium complexes that have been studied in relevant research activity as well as their application in coupling reactions.