In the past few years, the rising electromagnetic spectrum for wireless communications has been driven by the differences in the propagation characteristics of different bands, the demand for bandwidth, and the improved ability to utilize technology. In the field of communications, millimeter wave (mmW) low and medium frequency bands have been successfully engineered and started to be commercially deployed to meet the explosive growth in demand for wireless data transmission, especially for 5G communications. The optical communication for higher frequency electromagnetic waves with light waves as the carrier has also been maturely developed and applied for decades. Between conventional radio waves (millimeter waves) and conventional optics (far infrared), there exists a long-unused free spectrum resource, which is now collectively referred to as the terahertz (THz) band (01~10 THz). Due to the obvious advantages of the terahertz band in the field of high speed wireless communication, terahertz communication technology has the potential to become the core technology of 6G communication. It is foreseeable that the use of this technology will help 6G communication to realize the vision of full network coverage, high intelligence, and overall improvement of network security. This paper focused on the communication field, highly lighting the characteristics of the terahertz band, the types of devices, and process integration implementation technologies for building terahertz system functions. Finally, this paper predicted some application scenarios of terahertz communication technology, and then showed the contribution of this technology to the communication field and people's daily life.