In this paper,the forbidden band gap range and terahertz wave transmi ssion characteristics of two-dimensional titanium dioxide photonic crystal waveg uide are studied by using the finite-difference time-domain method.The titanium dioxide linear waveguide structure with a band gap width of 0.2262THz,the tit anium dioxide rectangular waveguide structure with a band gap width of 0.2728TH z and the titanium dioxide t-waveguide structure with a band gap width of 0.3166THz are designed.The transmission spectra of different waveguide structures an d the field intensity distribution under specific excitation source frequencies obtained by simulation are compared and analyzed.It is found that compared with the traditional waveguide,the two-dimensional TiO_2photonic crystal waveguide designed in this paper has high transmission efficiency of terahertz wave not on ly in the straight path,but also has high transmission efficiency in the rotati on path.The research results provide an important theoretical basis for the des ign and manufacture of terahertz devices,and provide an important theoretical r eference for the development of high-speed broadband wireless communication sys tems.