As we know,the intrinsic gain spectrum characteristics of broadband tellurite-based fiber amplifier(EDTFA)is not flat,so we designed a kind of dual-stage structure with a gain equalization filter between fibers. The theoretical simulation result shows that the fiber with 4000 ppm Er³⁺ concentration achieved a gain of 24 dB and noise figure of 5.5 dB with a slight gain excursion of 1 dB and the fiber with 6000 ppm Er³⁺ concentration also achieved a gain of 24 dB and noise figure of 5 dB with a slight gain excursion of 1 dB over a wide wavelength range of 1536～1608 nm through designing certain filters. The dual-stage EDTFA can meet the demand of WDM system after optimization.