Abstract: In recent years, with the rapid development of 5G technology, the construction of network scale is gradually launched. 5G communication network provides a better wireless communication solution for the development of energy Internet due to its characteristics of ultra-high bandwidth, ultra-low delay and ultra large scale connection. At the same time, there is an urgent need for a means to provide a unified time scale for business data. Through the analysis of 5G network time synchronization architecture, this paper studies the principle of 5G wireless terminal to achieve high-precision time service, builds a simulation model, deduces the factors that affect the time service accuracy, and verifies that by supplementing the delay error between the wireless terminal and the base station, it can effectively improve the high-precision synchronization index of 5G wireless terminal, and finally gives the some suggestions for high-precision time service of 5G wireless terminal.