With the evolution of the technologies for IoV to be intelligent and interconnected, V2X communication technology serves as a core technology for information interaction among intelligent connected vehicles, and an important technology to realize environment sensing for future autonomous driving. In order to provide wireless communication services with ultra-low delay, ultra-high reliability and ultra-large bandwidth, this article proposes architectures of 5G-V2X communication networks by exploiting the technologies of 5G new radio (NR), network slicing, and deviceto- device communications. We discuss their principles and key features, and foresee the challenges, opportunities, and future research trends. The applications of related technologies of the software defined network (SND) and multi-access edge computing (MEC) are also introduced. Finally, the technologies of information security and privacy protection are identified to support the diverse services and applications in the future 5G-V2X networks.