Abstract:The Maduo, Qinghai MS7.4 earthquake on May 22, 2021 broke the long-term M7 earthquake quiescence in Chinese Mainland, followed by the Menyuan, Qinghai MS6.9 earthquake on January 8, 2022. Understanding the precursory anomaly evolution before the two earthquakes is of great significance for the seismogenic process and short impending tracking of strong earthquakes in the Tibetan Plateau. In this paper, the anomaly characteristics, coseismic response, and post-earthquake effect of underground fluid at Zuoshu station in Xining City, Qinghai Province before the two earthquakes were analyzed, and the results show that the sudden drop of dynamic water level in Zoshu on February 25 and August 25, 2021 corresponds to the Maduo MS7.4 and Menyuan MS6.9 earthquakes, respectively. Furthermore, the trend turning anomaly of the dynamic water level and water temperature, which simultaneously appeared at Zuoshu station on July 10, 2021, has a certain spatio-temporal significance for the subsequent Menyuan MS6.9 earthquake. Through a discussion on the mechanism of water level and water temperature precursory anomalies at Zuoshu seismic station, it is found that the abnormal changes of underground fluid have a good short-term indication for strong earthquakes in the secondary block of Qinghai Province and its surrounding areas.