In this article new micro-scale hydrophone sensor has been introduced, designed and modeled. Proposed structure is absolutely feasible by current MEMS technology. Mechanical structure consists of two micro-scale arms which together hang a plat. In length of each arms embedded Mosfet transistor placed which on its’ gate plate very thin layer of piezoelectric material, PZT-5A, has been placed. Incident acoustic wave cause mechanical stress which induce surface charge on the interface of piezoelectric and gate layer. These charges will modulate transistor’s channel resistance and finally with employing electronic circuit electric current variation transfers to voltage variation. Simulation results indicated sensitivity of -160 dB in frequencies well below first resonance. In this article new micro-scale hydrophone sensor has been introduced, designed and modeled. Proposed structure is absolutely feasible by current MEMS technology. Mechanical structure consists of two micro-scale arms which together hang a plat. In length of each arms embedded Mosfet transistor placed which on its’ gate plate very thin layer of piezoelectric material, PZT-5A, has been placed. Incident acoustic wave cause mechanical stress which induce surface charge on the interface of piezoelectric and gate layer. These charges will modulate transistor’s channel resistance and finally with employing electronic circuit electric current variation transfers to voltage variation. Simulation results indicated sensitivity of -160 dB in frequencies well below first resonance.