High-performance photonic crystal fiber (PCF) has an important impact on the development of the full potential of complex terahertz systems. A new kind of PCF with D-shaped air holes in core region was proposed for terahertz (THz) region. The numerical simulation results showed that the proposed PCF has a flat dispersion of 0.09 ± 0.28 ps/THz/cm at 0.8-1.2 THz. At 1 THz, an ultra-high birefringence of 0.0595, a low effective material loss (EML) of 0.0557 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , and dispersion that can be considered zero were obtained. In addition, other characteristics of the proposed PCF were strictly analyzed, such as confinement loss, bending loss, and effective mode area. The PCF is expected to be used for short distance propagation of terahertz, polarization maintaining and sensing applications of terahertz waves.