The dual-stage L-band EDFA is optimized. At first, we make a simulation about the effect to the L-band EDFA by change of the proportion of EDF length of each stage by OptiAmplifier4.0 with other factors unchanged. Then we make a further optimization to the pump power of each stage to obtain the intrinsic flat gain spectrum as wide as possible. Based on that a experiment with a 42 meter long EDF is made, with the outcomings as follows: the ASE spectrum is from 1566.84 nm to 1606.80 nm within 3dB bandwidth,which is about 40nm,Within the L_band spectrum,the small signal gain is about 25dB,Noise figure is about 5dB.