Abstract: The background noise characteristics of 477 strong-motion stations in the Beijing-Tianjin-Hebei region were analyzed using power spectral density, whereas the horizontal-to-vertical spectral ratio (HVSR) was applied to investigate site response characteristics across regional stations. Background noise levels across the Beijing-Tianjin-Hebei region displayed distinct spatial patterns, with mountainous stations exhibiting the lowest and most consistent noise levels, whereas stations in plains and coastal areas demonstrated higher noise levels with greater susceptibility to anthropogenic activities and natural environmental factors. HVSR analysis revealed that plains and coastal regions with thick sedimentary deposits exhibited lower predominant frequencies (0.5～2 Hz) with pronounced low-frequency amplification effects, whereas mountain stations featured higher predominant frequencies (exceeding 5 Hz) attributable to bedrock exposure and elevated shear wave velocities. The spatial distribution and frequency domain characteristics of background noise levels were highly correlated with site response features, reflecting the combined effects of geological structures and environmental conditions, thereby providing scientific evidence for optimizing station distribution and improving seismic monitoring and early warning capabilities.