In order to study transmission characteristics of terahertz wave in new asymptotic porous photonic crystal fibers, finite element numerical analysis method was used for numerical simulation. The effects of effective mode area and core porosity on effective material loss, confinement loss and power distribution fraction were analyzed. The results show that, within the range of 0.5THz to 0.85THz, by introducing an asymptotic rectangular array of holes and elliptical holes into the optical fiber, zero dispersion, high birefringence of 0.0532, effective material loss of 0.1157/cm and confinement loss of 1.47×10-4 dB/cm are achieved. This study can be used to fabricate polarized THz waveguides, filters, etc. It is of great significance to study the long-distance and high-performance transmission of the new generation terahertz waveguides.