A polarization splitter based on dual-core photonic crystal fiber filled with tellurite glass in the central hole is proposed. The characteristics are studied by finite element method. The influences of the parameters $$d_{1}, d_{2}, \varLambda$$ d 1 , d 2 , Λ on the coupling length and coupling length ratio (CLR) are analyzed. The curves of coupling lengths of X-polarization, Y-polarization light dependence on the operable wavelength $$\lambda$$ λ are flat under the optimized structural parameters which is helpful to realize broadband polarization splitter. The simulation results indicate that the CLR could reach to 2.006 at the wavelength of $$1.55\,\upmu {\hbox {m}}$$ 1.55 μ m . The fiber length is only 510 $$\upmu {\hbox {m}}$$ μ m and the bandwidth of extinction ratio greater than 20 dB is 284 nm, i.e., from 1461 to 1745 nm which could be widely used in the large-capacity, broad-bandwidth and integrated optical communication systems. As the fiber length decreases, we find the bandwidth increases. But the extinction ratio at 1.55 $$\upmu {\hbox {m}}$$ μ m is lower than 20 dB as the fiber length is less than 510 $$\upmu {\hbox {m}}$$ μ m .