Abstract: The CTD sensor may acquire oceanographic environmental parameters as important basic data for oceanographic research, and the ROV, as an important ocean exploration tool and scientific research platform, has been widely used in the world major marine research institutions. According to the "HAISHI" ROV system architecture, the communication, control and power interface of the system are expanded, the FSI CTD sensor is applied to the ROV by the ROV expansion interface and acquire the CTD data in the ROV work station for regional marine geologic survey. The CTD data quality meets the requirements of the marine geological survey lastly.