Underground observation instrument for cable conduit in power well and application method

The invention discloses an underground observation instrument for a cable conduit in a power well and an application method. A detection device is composed of a main framework and a video sampling device mounted on the main framework and is used for sampling cable conduit situations under the underwater power well and outputting video signals of the cable conduit situations under the underwater power well. A monitoring device is connected with the detection device through a three-proofing transmission cable and is used for receiving the video signals of the cable conduit situations under the underwater power well output by the detection device, displaying the cable conduit situations under the underwater power well in real time, shooting and photographing the cable conduit situations under the underwater power well, and preserving the obtained video and image information. An underwater camera is adopted and combined with a night vision white-light lamp so as to transmit the cable conduit situations under sewage in the well to an image displaying module through the video signals, and workers can observe through the image displaying module. Thus, underground observation steps are simplified, underground observation time is shortened, and the working efficiency of operators is improved.