Experimental research on Yb3+/Er3+ co-doped distributed Bragg reflection fiber laser (DBR-FL) hydrophone is carried out. The Yb3+/Er3+ co-doped DBR-FL, with a resonator length of 8 cm, could gain an output of 0.263 mW when the pump power is 50 mW. A Michelson fiber interferometer with Faraday rotator mirror and phase generated carrier (PGC) demodulation scheme, is used to interrogate acoustic signal acted on the Yb3+/Er3+ co-doped DBR-FL hydrophone, and the acoustic pressure sensitivity is gained by comparison with the standard piezoelectricity hydrophone. The fluctuation of sensitivity at single frequency is less than ±0.6 dB during repetitious tests. The frequency response is gained from 80 Hz to 2.5 kHz. Comparison experiments are also carried out on DFB-FL hydrophone, which gains a similar frequency response, showing that the fluctuation of frequency response is caused by unsealed hydrophone structure and test system.