The invention discloses a paste filling pipeline pipe-plugging monitoring device and a monitoring method. The device comprises a monitoring pipe and a magnetic substance concentration testing device; and the monitoring pipeline is arranged on a filling pipeline of a paste, and the magnetic substance concentration testing device is connected with the monitoring pipeline. The filling paste is added a certain proportion of magnetite ore, the concentration of the magnetite ore of the paste at different locations in the pipeline are measured in a conveying pipeline, when pipe plugging appears, and the concentration of the magnetite ore monitored in the positions in front of and behind the pipe-plugging position in the pipeline are significantly different, so that the pipe-plugging position is positioned precisely. According to the paste filling pipeline pipe-plugging monitoring device and the monitoring method, paste filling pipeline pipe-plugging automatic monitoring is realized, the possible pipe-plugging location can be predicted timely and accurately; the monitoring device is simple in structure and easy to operate; and a plurality of monitoring points can be arranged on the paste conveying pipeline, all monitoring points are finally connected to the magnetic material concentration testing device, and cost is reduced.