Abstract: In order to achieve the purpose of minimizing the flatness of Raman gain under the condition of high net gain, particle swarm optimization (PSO) algorithm was used to optimize the pump parameters of As-S fiber and tellurium based fiber amplifier. Theoretical analysis and experimental verification were carried out. Using the above method to compare the obtained three sets of optimization results, it is found that the average gain is 53.25dB and the corresponding gain flatness is 0.30dB on the cascaded Raman fiber amplifier with a bandwidth of 40nm. The results show that, compared with the traditional fiber amplifiers, the performance of the cascaded fiber amplifier will be significantly improved after the optimization of the power and wavelength of each pump light by using particle swarm optimization algorithm, which has a certain practical value in the future fiber communication.