Abstract: Short construction period is one of the advantages of mobile substation. However, most mobile substation communication systems still adopt the way of laying fixed optical cable and configuring optical transmission equipment, which brings the problems of long construction period and low investment utilization rate of communication system. The characteristics of 5G communication, such as large bandwidth, low latency, multi connection, edge computing and network slicing, create opportunities for the improvement of power communication construction level. In this paper, 5G communication technology is introduced into the construction of mobile substation, and the particularity of power communication system is fully considered. The time delay, reliability, bandwidth, security and other aspects are elaborated in detail. A deployment mode of 5G applied to power communication construction which is suitable for the security protection requirements of power monitoring system is proposed, and a rapid construction mode of mobile substation communication system based on 5G is given.