Abstract:The signal transferring in the DWDM system is affected by SRS effect and attenuation, and the receiving signal and noise will simultaneously affect the communication result. In this paper, based on the computer model,the influence of various factors on BER was analyzed with theoretical derivation and numerical simulation for three cases. The results show that only attenuation has little influence on BER, while under the condition of both SRS and attenuation, the BER increases rapidly as the rise of the initial power. Furthermore, when simultaneously considering noise, attenuation and SRS effect, the BER will be greatly affected.