A novel passive homodyne Michelson interferometric fiber-optic hydrophone of anti-aliasing has been manufactured and demonstrated. This new fiber-optic hydrophone consists of a conventional mandrel fiber-optic hydrophone and a metal cylindrical Helmholtz resonator. The acoustic pressure phase sensitivity response has been measured in a standing-wave tube filled with water. Experimental results show that this new fiber-optic hydrophone is of acoustic low-pass filtering, which makes it available for suppressing high-frequency components in acoustic signal and eliminating aliasing in the future sonar system. The low frequency sensitivity of this fiber-optic hydrophone, as determined by the length of the sensing fiber and the performance of the elastic layer, is -159 dB (0 dB=1 rad/μPa). The frequency response has a resonance peak near 1150 Hz, which is determined by the cylindrical Helmholtz resonator. There is a measured roll-off of 50 dB/octave over the range of 1150～2280 Hz. The acoustic sensitivity attenuation beyond 1500 Hz is bigger than 10 dB. This new fiber-optic hydrophone is very important for enhancing the operation performance of the future sonar system.