Gain characteristics of small signal in L-band Erbium-doped fiber amplifier (EDFA) are analyzed with the numerical simulation using Giles model. The results show that the optimal fiber length varies with input signal wavelength, in general, shorter wavelength demands shorter fiber length. 7 m and 9 m L-band EDF are employed to construct L-band EDFAs respectively. Evaluation of EDFAs is made by experimental comparision of their amplified spontaneous emission (ASE) spectr, gains and noise figures (NF), and the results show that the fiber length is crucial for proper gain characteristic. On the basis of these numerical, experimental study and also considering their C-band characteristics, optimal ASE spectrum related to the best behavior of L-band signal amplification is presented.