Abstract: Traditional terahertz (THz) single-mode single-polarization (SMSP) fibers are mostly designed on the basis of solid fibers, which increases the THz wave transmission loss. In recent years, there have been a few reports about THz SMSP hollow core fibers; however, the fibers have narrow bandwidth, they can only work around a single frequency, which reduces the application value and technical advantages of single-polarization devices in THz networks. In order to solve these problems, a broadband THz SMSP fiber device was proposed. The fiber can achieve SMSP transmission from 1.63 THz to 1.73 THz with a bandwidth more than 0.1 THz. It has great significance for the establishment and application of THz communication network.