The basic architecture of 5G wireless communication system in coal mine is proposed: 5G core network, base band unit (BBU), remote radio unit hub (RHUB) and 5G base station are connected by 5G bearer network to realize signaling transmission among network elements. Underground 5G base stations and antenna are used to realize underground wireless signal coverage. After the base stations are converged through a RHUB, they are connected to BBU and connected to the 5G core network. The advantages and disadvantages of two kinds of 5G core network construction schemes are compared, namely user plane function/mobile edge computing (UPF/MEC) sinking and independent private network. This paper studies the bearer networks between 5G core network and BBU, between BBU and RHUB, between RHUB and 5G base station. This study focuses on the characteristics and application scenes of the three bearing methods commonly used in the bearer network between the 5G core network and the BBU, namely the optical fiber direct connection, the slicing packet network (SPN) and the 5th generation fixed network (F5G). The design schemes of coal mine 5G base stations, 5G terminals and 5G communication modules are proposed. Combining the characteristics of 5G communication technology and the requirements of coal mine intelligence development, the typical applications of 5G wireless communication systems in coal mines are discussed, such as integrated communication, high-bandwidth service applications, intelligent working face service application, remote control of mining vehicles or unmanned driving, etc. It is pointed out the further optimization directions of the coal mine 5G wireless communication system, including the design of miniaturization industry 5G core network, the low-power and intrinsically safe design of coal mine 5G base stations and other equipment, the underground application of 5G equipment in the 700 MHz frequency band to improve the coverage of 5G base stations, the customization of coal mine 5G mobile terminals and the development of industry APPs, the development of low-power 5G communication modules, industry application scenes in combination with on-site needs, etc.