The invention discloses a drifting detection underwater robot device and a control method, and belongs to the technical field of detection underwater robots. A robot main body is of a torpedo-shaped structure; hydrologic detection equipment ADCP (Acoustic Doppler Current Profiler), ranging sonar and an emergency load rejection device are carried at the fore body of a robot; a pressure-resistant cabin is arranged at a middle cabin section; the pressure-resistant cabin is divided into an energy source cabin and a control cabin; two high-energy density lithium batteries are arranged in the energysource cabin and are correspondingly used for supplying power to a power system and a control system; a conformal antenna (comprising Beidou positioning and communication, radio and WiFi), DVL, a depthometer and ranging sonar are carried at the tail section; high-efficiency propellers are arranged on the left side and the right side of the tail of the robot; and vertical channel propeller is arranged at each of the front and rear of the robot. According to the surrounding environment and task instructions of the robot, the effect of selecting to start or close a drifting mode is intelligentlyrealized, so that low-power-consumption, long-voyage and long-time detection monitoring tasks are realized.