Abstract: Combined with the moderate seismic activity (M_L≥4.0) in the border region of Beijing-Tianjin-Hebei since 1992, the fluctuation characteristics of small earthquake activity in this area were analyzed and the anomaly index was extracted. It is found that after the continuous enhancement of M_L2.0~2.9 seismicity for four months with a frequency of ≥10 in the border region of Beijing-Tianjin-Hebei, earthquakes above ML4.0 are more likely to occur within 8 months. The prediction efficiency of this prediction index is analyzed. The earthquake corresponding ratio is 80%, the false ratio is 20%, the omission rate is 33%, R=0.57, R₀=0.44, indicating a good prediction efficiency. It can be used as a short-term prediction index to provide prediction basis for the analysis of significant earthquakes in the border region of Beijing-Tianjin-Hebei. This paper also discussed the causes and reliability of high-frequency anomalies in small earthquake activities.