Based on the 1-second sampling data of 14 geomagnetic stations in Gansu, Qinghai, and Sichuan areas, we analyzed the temporal and spatial variation characteristics of the geomagnetic vertical intensity polarization anomalies before Menyuan, Qinghai M_S6.9 earthquake on January 8, 2022. The results show that there were high value anomalies of geomagnetic vertical intensity polarization at the end of October 2021. The anomalous stations are mainly distributed in Qinghai, Gansu, and Sichuan areas. The Menyuan earthquake occurred 73 days after the occurrence of anomalies, and the epicenter was near the anomaly threshold line of high polarization. It is also found that the geomagnetic polarization anomalies have certain temporal and spatial variation characteristics. In terms of time, the polarization anomalies of different stations have good time synchronization; spatially, the anomalous high-value area of polarization shows the characteristics of appearing near the epicenter, then expanding continuously, and finally shrinking toward the epicenter. In addition, the normalized zero polarization value, the anomaly duration, and the epicentral distance of anomalous stations show a negative correlation. As the epicenter distance of abnormal stations decreases, the normalized zero polarization value becomes higher and the anomaly duration becomes longer. It is consistent with the attenuation characteristic of the seismic electromagnetic signal. According to the spatial-temporal relationship between polarization anomalies and earthquakes, the high-value anomaly of geomagnetic polarization corresponds to the subsequent Menyuan M_S6.9 earthquake.