The influence of incident optical power on the transmission distance tolerance of high-rate communication is analyzed. In order to solve the problem which limits the incident optical power, a system solution based on remote Er-doped amplification technology(REOA) is proposed, which improves the equivalent incident optical power and the transmission distance tolerance greatly. It is theoretically analyzed that the equivalent incident optical power is related to the loss of the fiber in the front of REOA and the output power of REOA. The experiment of 400 Gb/s transmission demonstrates that the equivalent incident optical power of REOA system is 14.27 dB higher than that of conventional system, and the transmission distance is extended by about 70 km.