The 20 dB-bandwidth of 125 nm covering the whole C, L bands and part of S band of supercontinuum (SC) in a 4.2 km dispersion-shifted fiber (DSF) was obtained in the experiment, which was based on the actively mode-locked erbium-doped fiber laser (AMLFL) with the repetition rate of 10 GHz and the pulse duration of 7.97 ps. The dispersion-shifted fiber (DSF) was pumped by the output pulses from the AMLFL without being compressed. In a DSF, the supercontinuum results from combined interaction of nonlinear effects including self-phase modulation (SPM) and cross-phase modulation (XPM). The influences of peak powers and wavelengths of pumping pulse on supercontinuum (SC) spectrum were experimentally investigated. It is clear that the generated supercontinuum could be broadened further when the pump pulse peak power is increased; The broader supercontinuum could be got by optimization of pump wavelength; At the same time, the characteristics of pulses which are filtered out from supercontinuum spectrum by tunable filter with 0.4 nm bandwidth were studied. The stable, narrow optical pulses with pulse-width of 8.90～9.80 ps and time-bandwidth product of 0.44～0.49 were filtered out from the supercontinuum at different wavelengths.