Multi-wavelength conversion was simultaneously achieved by using nonlinear optical loop mirror (NOLM).The maximum separtion of the wavelength conversion between the control laser and the signal laser is larger than 25 nm. In the system, the gain switched distributed feed-back laser-diode is used as the control pulse with the pulse width of 20 ps, the spectrum-sliced fiber amplifier light source is used as the signal lasers with multi-wavelength output. The performance of the converted signal with different wavelength depends on the control optical power or the direction of the polarization controller in NOLM.