The invention discloses a PSD-based tracked automatic monitoring device and method for an operational period of tunnels. The device comprises a track device, a measuring device and a measuring system, wherein the track device comprises an umbrella-shaped track and a umbrella-shaped hook; and the measuring device comprises a laser measuring box and a PSD reading box; and the measuring system comprises a data transmission system, a data management and analysis system, a warning system and a central control platform. The invention further discloses a corresponding monitoring method based on the tracked automatic monitoring device. The full monitoring process can be controlled by virtue of a computer, and data is wirelessly transmitted and processed. The tracked automatic monitoring device is light, convenient and easy to mount, the system is stable, and the functional developability is strong. By virtue of the monitoring method, the monitoring efficiency is improved, and the labor is saved.