Abstract: In order to study characteristics of a backward pumped distributed broadband fiber Raman amplifier,with multisemiconductor laser at wavelength of 1426nm,1440nm,1460nm,1475nm and 1495nm as pump source,signal amplification at bandwidth of 80nm in C+L band was realized and better gain flatness and polarization correlation were obtained.The on-off gain was 10.7dB,gain flatness was 1.5dB,and the maximum noise index was-1.96dB.Experiment results indicated that the pump wavelengths and pump power of the fiber Raman amplifier selected according to the numerical value calculation were reasonable,all technical parameters of the system satisfied requirements of the fiber communication.The resuhs will have very import guidance effect for the development of optic communications.