Abstract: From the point of view of system design, this paper introduces the configuration of fiber-optic interferometric hydrophone array and modulate demodulate, technique using frequency division multiplexing technique based on phase generated carrier, on the foundation of which we place emphasis on demonstrating the relationship among the number of units N, the detectable signal amplitude D and the detectable frequency ω_s through analyzing the frequency spectrum of the output signal of the J×K array and the key factor which restrict N, D,ω_s to increasing. We specially analyze the maximum phase shift and the law of its variation according to frequency. At last we verify the result induced from some relative theory through experiment.