With the explosive growth of wireless data rate, the terahertz band(0.1~10 THz) has attracted increasing attention due to its rich frequency resources. The terahertz photonic communication technology has advantages such as broadband, high modulation efficiency and low harmonic distortions. It is expected to greatly promote the wireless transmission data rate toward the Tbit/s level. Based on the review of the key technologies for realizing ultra-high-rate terahertz photonic communication, including terahertz communication transceivers, digital baseband signal processing technologies, terahertz photonic communication system architectures and experimental demonstrations, the future development trends of the terahertz photonic communication technologies are discussed. The application scenarios of terahertz photonic technology from the micro to macro scales are also analyzed.