Detection device and detection method for drainage port backflow drainage pipe network

The invention discloses a detection device and a detection method for a drainage port backflow drainage pipe network. The detection device comprises a square elbow and a shaft, a plugging pipe is arranged at one end of the square elbow, a connecting pipe is arranged at the other end of the square elbow, and the shaft is installed on the connecting pipe. The detection method comprises the following steps: S0, determining a suspected well; s1, assembling the detection device; s2, the detection device is put into water, a plugging pipe is aligned to the discharge port and then inserted for plugging, and the detection device and a pipeline in the suspected well form a communicating vessel structure; s3, taking water from the on-site surface water body by using a water taking tool, adding an isotopic tracer agent to form a mixed water body, pouring the mixed water body into the detection device from the top of the shaft, and enabling the mixed water body to enter the suspected well; s4, water quality sampling and