In this paper,we used the maximum entropy spectrum method to study the geoelectric field data observed by the Songshan,Shandan,Gaotai,and Guazhou stations around the epicenter of Menyuan M_S6.9 earthquake on January 8,2022,and analyzed the power spectral density (PSD) variation of geoelectric field before and after the earthquake.The results show that:(1) The increased PSD of low frequency components was recorded before the Menyuan M_S6.9 earthquake by the four stations;(2) The changes of PSD before the Menyuan earthquake were basically synchronous in the four stations;(3) Combined with the microfracture mechanism and the viewpoint of "multi-point field",we drew the conclusion that the electromagnetic anomalies before the Menyuan M_S6.9 earthquake were mainly caused by the electromagnetic radiation generated by the focal development.