On May 22, 2021, an M7.4 earthquake occurred in Maduo County, Qinghai Province. In this study, the cave strain observation data of Tongren, Tangchang, Wudu, and Guza stations from May 1 to 22 were selected and processed with the multi-scale wavelet decomposition method. The results showed that at scale 11, the amplitude of NS components at two close stations increased significantly before the earthquake. Generally, the smaller the epicentral distance is, the larger the deformation amplitude is. There were obviously different characteristics of the vector trajectories during May 10-14 and 16-20. In addition, the multi-scale wavelet decomposition of geomagnetic vertical component at Dawu and Hezuo stations showed that the amplitude increased in the same period (scale 18), which also confirmed the reliability of the strain anomaly. We believe that this strain anomaly is the eastward pushing result of the Qinghai-Tibet block, and is related to the consequent MaduoM7.4 earthquake. Combined with the research results of other scholars, we inferred that this may be related to the movement of the high conductive layer beneath the epicenter. However, this is only a preliminary study, and the detailed seismogenic environment and mechanism need to be further studied.