Due to the increasingly complex electromagnetic environment, the electromagnetic space situation has the characteristics of integrity, dynamics, relevance, visibility, mass, multi-dimensionality and so on. The study on the electromagnetic space situation provides an important theoretical support for improving the comprehensive performance of the frequency system, realizing the spectrum sharing of the mobile communication system and ensuring the spectrum security of major security activities, which has gradually become one of the most dynamic research directions in the spectrum field. The related technologies of electromagnetic space situation research at home and abroad are highlighted in this paper, and the representative work is systematically introduced. The importance and development status of electromagnetic space situation research are summarized, and the challenges in this field in the future are put forward.