Based on the electron density data observed by Langmuir probe and the Oxygen ion density data observed by plasma analyzer of Zhangheng-1 electromagnetic satellite, the characte-ristics of electron density and oxygen ion density anomalies before the Menyuan, Qinghai M_S6.9 earthquake on January 8, 2022 were analyzed, and the anomalies before previous earthquakes were also summarized. The results show that high values of electron density and oxygen ion density appear 11 days before the Menyuan M_S6.9 earthquake. Through the statistical analysis of ionospheric anomalies before 16 earthquakes, it is found that anomalies are generally observed within 6 days prior to earthquakes, and most of them occur before strike-slip and thrust earthquakes. The acoustic gravity wave mechanism and electric field mechanism were considered as the possible generation mechanism of anomalies.