Abstract: Recently, with the rapid development of space-air-ground technology, the real-time and high-quality wire-less communications between versatile satellites in different orbits and various mobile carriers on the ground require the antenna to have the characteristics of beam scanning, easy conformation, light weight, low cost and low power consumption. Compared with reflector antennas and phased arrays, parallel plate waveguide (PPW) based continuous transverse stub (CTS) antenna can easily satisfy the abovementioned demands. Firstly, the operation principles of CTS antenna and its beam scanning are expounded. Secondly, the research progess of mechanical scanning and frequency scanning antennas are analyzed and summarized. The mechanical beam scanning of CTS antenna in elevation can be realized by three means: moving the feeding source, variable inclination CTS antenna, and rotating the phase shift metasurface placed above the CTS antenna. Simultaneously, the scanning in azimuth could be achieved by rotating the whole antenna, so the two dimensional mechanical scanning is realized. Finally, the problems, chanlenges, and further research directions of CTS antenna are discussed.