The electromagnetic (EM) coupling between metal nanoparticles (NPs) is of essential importance in nanoplasmonic systems, leading to a variety of fundamental studies and practical applications. The successive investigations in this field not only bring forward surprising optical effects in nanoplasmonics, but also allow revealing other novel chemical/physical properties in relevant systems. In this article, we will discuss the EM coupling in four types of typical plasmonic nanostructures, i.e., single aggregated metal NPs, asymmetric metal NPs dimers, nano-manipulated metal NPs and supported metal NPs on a substrate, and outlook the corresponding impacts in understanding physics and extending applications.