To overcome the high pump power of Raman amplification the remotely pumped erbium doped fiber amplifiers (RP-EDFA) are introduced in ultra-long haul dense wavelength division multiplexing (DWDM) systems. Firstly,the noise performance of a simple co-fiber RP-EDFA is investigated experimentally and theoretically,then the design method is discussed. The OSNRs and nonlinear phase shifts of typical systems based on RP-EDFA and backward pumped Raman amplification are compared theoretically,showing that RP-EDFA can efficiently reduce pump power and is appropriate for the ultralong span application. Finally,Q value of the typical transmission system is simulated. The results show that using RP-EDFA pumped by only 220 mW,1000 km transmission of a 40×11.6Gbit/s system with a span distance of 167 km can be achieved,with 4.4 dB margin of Q value.