Abstract: By introducing the wavelength distribution and shift of the gain spectrum of semiconductor light amplifiers(SLA) into the theor etical model that describes the dynamic process of picosecond optical pulses pas sing through the amplifiers,the influence of the wavelength distribution and shift of the gain spectrum on the temporal distribution of amplified pulses is numerically studied. The results reveal that for the input pulses with the same tem poral distribution but different wavelengths passing through the SLA,the output pulses have obvious distinctions in their shapes such as the peak power and the time of the appearance of the peak;under the SLA biased at various currents,the output pulse has obvious differences between including and neglecting the gain shift and wavelength dependence for a input pulse passing through the SLA.