Abstract: The paper presents the solutions of coupled-waves equations of degenerate four-wave mixing (DFWM) numerically. The results show that the power increase of pump wave can decrease the period of energy interchange of pump and anti-Stokes waves, and the power transfer relationship of pump and anti-Stokes waves in specific distances can be used for all-optical signal amplitude reshaping. The all-optical signal amplitude reshaping principle is explained from this point of view, and an all-optical signal reshaping system is designed accordingly. The system is tested through the eye diagrams of input and output signals, extinction ratio (ER) and Q-factor by simulating. It improves the ER and Q-factor from 9.46 dB to 30.4 dB and 15.95 to 180.4 respectively.