The invention discloses an underwater safety isolation device for a submarine pipeline. The underwater safety isolation device comprises a central control device, wherein the central control device is connected with a main control station, a control plate for an underwater safety isolation valve, an overwater umbilical cable terminal device, a control umbilical cable for the underwater safety isolation valve, a hydraulic performing mechanism and the underwater safety isolation valve in sequence; a hydraulic power unit is used for adjusting a hydraulic power source through the control plate; the main control station is used for exchanging data with the central control device, processing and transmitting an instruction to the control plate for the underwater safety isolation valve after receiving a switching on or off signal of the underwater safety isolation valve of the submarine pipeline, sent by the central control device, switching on or off a solenoid valve in the control plate, enabling the solenoid valve to conduct a hydraulic oil supply and return loop, and switching on or off the underwater safety isolation valve. According to the underwater safety isolation device, the submarine pipeline can be safely isolated before being connected to a fixed platform for marine oil or a floating type production facility, and the production facility is subjected to position state displaying and remote operation.