In this work, we propose and numerically analyze the large-core tellurite glass (TWPN/I/6) photonic crystal fibers with an octagonal cladding structure. The wavelength-dependent effective refractive index and dispersion are investigated over the 1.0-6.0 µm spectral range. The results show that the maximum and minimum effective refractive indices are 2.051 and 2.005, corresponding to structures with Λ = 1.5 µm; d/Λ = 0.3 and Λ = 0.875 µm; d/Λ = 0.7, respectively. Furthermore, two optimized fibers (Λ = 0.875 µm; d/Λ = 0.3 and Λ = 1.0 µm; d/Λ = 0.3), exhibit flat dispersion profile with low values at suitable pump wavelengths, confirming their potential application in mid-infrared supercontinuum generation.