To address the challenges of array loss and transmission link loss in long-distance large-scale optical fiber hydrophone systems, which are difficult to effectively compensate using distributed fiber raman amplifiers （DFRA）, as well as the strong pump light relative intensity noise （RIN） generated during high-gain amplification, a hybrid amplification technique combining remote optical pumped amplification （ROPA） with DFRA is proposed. By establishing a correlation model between the system optical signal-to-noise ratio （OSNR） and demodulated phase noise, the impact of ROPA on system OSNR and demodulated phase noise is analyzed. The experimental results show that in a 16-wavelength×8 time-division multiplexing （TDM） 100 km long-range phase-generated carrier（PGC） demodulation system, the application of ROPA reduces the system demodulated phase noise by 7.7 dB, achieving -100.4 dB@1 kHz. After optimizing the optical path structure of the remote gain unit （RGU）, the system demodulated phase noise reaches -101.5 dB@ 1 kHz.