Abstract: As a kind of potential mineral resources in the ocean,cobalt-rich crusts have attracted people's attention gradually. The study demonstrates that the small-scale submarine relief is an important factor affecting the distribution of cobalt-rich crusts. DTA-6000 acoustic deep-tow system is the first set of towing deepwater observation system with independent intellectual property rights by China. Its maximum working depth is as deep as 6000 meters. The high-resolution bathymetric sidescan sonar and sub-bottom profile installed on DTA-6000 system can get high resolution submarine microrelief features and sub-bottom profiles. The sounding coverage is 600 meters,the side scanning coverage is 800 meters. The acoustic deep-tow system is applied for cobalt-rich crusts resource investigation as a conventional device due to its efficiency and low cost. In the 29^th cruise, the DTA-6000 finished two survey lines with a total length about 50 km on the slope of MA seamount. This paper introduces the application of DTA-6000 acoustic deep-tow system for the investigation of cobalt-rich crusts, and the acquired results are analyzed.