The invention relates to an electromagnetic environment long-term continuous monitoring system for an extra-high voltage alternating current/direct current parallel transmission line. An infrared probe is used for sensing head and end point markers and collection point markers; the infrared probe can sense the markers, so that the markers can be adopted as triggers for signal acquisition and position markers, and therefore, a monitoring vehicle can reciprocate on a track and continuously collect various monitoring data (such as ground combined field strength, environmental electromagnetic field intensity, radio interference monitoring signals and noise values) through a signal acquisition device within the range of the track range; the parallel transmission line can be monitored based on analysis on the collected data signals; and the automatic collection of the data is realized, and the whole process does not require manual intervention. The system can be applied to monitoring in various meteorological environments.