Abstract: Based on the data tracking event record of electromagnetic discipline from 2014 to 2021 in Anhui Geophysical observation network, this paper sorted out 6 kinds of typical interference events. The causes of interference and variation characteristics are deeply analyzed. The main factors affecting the quality of electromagnetic observation data of Anhui electromagnetic network are summarized. Based on the causes of interference and observation experience, the corresponding countermeasures or suggestions are put forward. It lays a foundation for further analysis and application of precursory observation data.