Before the M_S6.6 earthquake happened in Jinghe, the borehole strain gauges of Nilka, Gongliu and Xiaoquangou seismic stations recorded significant abnormal changes in high-frequency signals, and it was reliable to confirm the abnormalities through on-site abnormalities. In this paper, the similar signals are extracted by the over-limit rate analysis method, and the abnormal signal intensity before the earthquake is quantitatively described. the results show that the super-threshold phenomenon occurs in different degrees before the earthquake, and the anomaly is remarkable. Two of them are changes in the impending earthquake.