The utility model discloses an on - -spot measuring device of seabed substrate acoustics, include detection device and controlling means on water under water, detection device includes altimeter, video and lighting device, acoustics acquisition unit, probe rod, hydraulic drive device and controller under water, install acoustic transducer on the probe rod for insert in the seabed and detect deep -sea sediment's acoustics parameter, the probe rod is connected to the hydraulic drive device for the drive probe rod inserts or leaves the seabed, the controller is used for controlling the operationof hydraulic drive device to reach controlling means on water on the altitude signal of gathering the altimeter. The utility model provides a traditional far -reaching extra large seabed acoustic sounding device and instrument can't carry out real -time online continuous observation's defect, for substrate acoustic characteristic in -site measurement research in seabed provides the data and the information of visual and multi -parameter, high real -time, provide important technical support platform for the ocean scientific research personnel acquires the real -time acoustics data in seabed fora long time with the parameter.