When self-similar pulses are generated in the gain fiber, the effect of gain saturation energy and gain bandwidth on pulse distortion increases with the increasing energy, resulting in the inability to obtain highenergy, highquality selfsimilar pulses. This paper focuses on the use of dispersion decreasing fiber (DDF) to further optimize the self-similarity evolution process of pulses in gain fibers, ensuring the quality of self-similarity pulses with high-energy in gain fibers. The feasibility of using DDF to optimize self-similar pulses generated in gain fibers is analyzed theoretically and verified numerically. The effect of different types of DDF on the optimization effect is also analyzed. The simulation results show that after using DDF optimization, the self-similarity evaluation factor decreases from 0.051 7 to 0.028 6, indicating that DDF effectively optimizes the self-similarity pulses generated by gain fibers. Meanwhile, by analyzing different shaped DDFs, it was found that hyperbolic shaped-DDF can achieve the best optimization results, obtaining low pedestal ultra short pulses with a peak power of 11 034 W and a full width at half maximum (FWHM) of 129 fs. This study has certain implications for obtaining self-similar pulses with high-energy and high-quality.