Abstract: This paper presents an in-situ geoacoustic measurement system for mid-frequency band based on high-frequency micro-vibration penetration technology, designed for in-situ measurement of mid-frequency sound speed and attenuation coefficients of seafloor sediments. The system consists of five subsystems: mechanical-hydraulic, transducers, sound wave transmission and acquisition, control, and auxiliary measurement. A “high-frequency, synchronous-speed, reverse-rotation, double vibration-motors” technique was innovatively proposed to serves as the driving force for probe penetration, which enhanced penetration depth and speed while reducing sediment disturbance caused by vibration. The independently developed transmitting transducer can cover a frequency band of 1 kHz to 20 kHz, while the receiving transducer achieves a sensitivity better than –196 dB. Transmitting high-fidelity CW pulses improves the accuracy of sound speed and attenuation coefficients of seafloor sediments. Offshore tests demonstrated that the system operates stably and reliably, with the key technical specifications meeting design requirements. In April 2025, the system was deployed aboard the R/V “Xiangyanghong 01” and finished 62 stations of in-situ geoacoustic measurements on the northern continental shelf of the South China Sea, obtaining mid-frequency sound speed and attenuation coefficients of the seafloor sediments. It can provide important environmental data support for accurate prediction of ocean sound field.