A new global fifth generation (5G) mobile communications system standard: 5G network brings users the experience of ultra-high speed and ultra-low delay, but also brings greater challenges to the user equipment (UE) power consumption. It is very important to develop power saving technology of UE. Reducing the power consumption of UE and prolonging the battery life is one of the key indicators for 5G to be widely used. This paper provides an overview of the UE power saving technologies of 5G NR, including discontinuous reception (DRX), wake-up signal (WUS), radio resource management (RRM) measurement relaxation and paging enhancement, and then power saving on the NR Reduced Capability (RedCap) UE has been studied. The issues are analyzed, and corresponding solutions are proposed. The advantages of the proposed solution is that the UE can reduce the energy consumption caused by unnecessary detection and measurement be adjusted timely and flexibly according to different situations.