This paper presents the development and testing of a remotely operated vehicle (ROV). The outstanding ability of this ROV lies in its underwater hovering positioning control. At the same time, it is equipped with a seven-function underwater electric operation manipulator and the master-slave control mode is adopted. These are obvious advantages over other medium-sized ROVs. The control hardware architecture and control software architecture of this ROV are also provided. Finally, the test results of the depth trajectory tracking control, heading trajectory tracking control and hover control in the lake environment are presented and analyzed