The utility model discloses an endoscope detecting device of a steel vertical pipe of a subsea pipeline. The endoscope detecting device comprises an inner observation probe (1), a processor and a display device (2), wherein the inner observation probe (1) enters the vertical pipe from an instrument pipe base of the vertical pipe, and is used for probing the interior of the vertical pipe and outputting camera signals; the processor is used for receiving and processing the camera signals and outputting image signals according to a processing result; the display device (2) is used for displaying an image inside the vertical pipe according to the image signals; and the inner observation probe (1) and the display device (2) are connected with the processor. The endoscope detecting device has the beneficial effects in that a detection process is simple and rapid; and auxiliary operation which is difficult to carry out on a platform such as a scaffold and the like is not needed in a detection process. Compared with the traditional ultrasonic erosion detection technology, the endoscope detecting device has high operation efficiency, and can be used for completing detection content which is completed by the traditional ultrasonic technology for 3-5 days within 1-2 hours. Compared with the traditional ray detection technology, the endoscope detecting device is safe and reliable, prevents workers on the platform from any danger, and has no need of adopting specific security methods aiming at the technology in an operation process.