Lower hybrid current drive (LHCD) system is one of the important tools to sustain long pulse discharge and improve plasma confinement in tokamak device. The LHCD system with 4.6 GHz was developed in 2013 and applied for experiments in 2014 on EAST. The system consists of microwave source, transmission line, multi-junction antenna, high voltage power supply, monitor system, water cooling system, and high power microwave test system, and so on. In EAST experiments, the 4.6 GHz LHCD system is used to maintain steady-state plasma, control the plasma current profile so as to realize high confinement plasma operation.