Abstract: This paper presents the design of a broadband, low-noise underwater acoustic general-purpose measurement amplifier, based on signal conditioning technology. Serving as the primary stage amplifier for hydrophones, it amplifies weak underwater acoustic signals, thereby enhancing the signal-to-noise ratio essential for subsequent filtering and processing stages. The design features twin JFET field-effect transistors in the input stage to optimize impedance conversion and minimize bias noise. The amplifier boasts a high gain capability, with a maximum of 110 dB, a dynamic gain range of −30 to 110 dB, operating bandwidth from 1 Hz to 200 kHz, and equivalent input noise below 5 nV/√Hz. Gain levels can be controlled via an RS232 bus. Key attributes include adjustable gain stages, broad bandwidth, low noise, high linearity, and versatility. Comparative tests with similar foreign amplifiers confirm that this design fulfills technical specifications, delivering performance on par with international counterparts and demonstrating efficacy in practical applications.