With the development of high temperature superconducting (HTS) materials, HTS technology has been used to develop superconducting cables which have practical applications in power transmission systems. Compared with the traditional cables, HTS power transmission has various advantages: large capacity, low loss, small volume, light weight, high reliability, saving resources, environment friendly and so on. It is expected to play an important role in the development of power grids in the future. This paper introduces the structure and characteristics of the HTS cables, design principle, current distribution in conductor layers and AC loss; discusses the main technical issues of the HTS cables; and introduces the application of the HTS cables in AC and DC transmission systems including current HTS cable projects and their performances worldwide.