Abstract: Two tall building models with square cross-sections were experimentally studied in TJ-1 Boundary Layer Wind Tunnel with high-frequency-force-balance technique to investigate the interference effects on across-wind dynamic response. Another wind tunnel test on two building models, which had the same square cross-sections but the principal model is aeroelastic was also carried out to further study the interference effects, which verified the results from the high-frequency-force-balance test. The influence of turbulence intensity of flow field on across-wind dynamic interference effects is analysed. The artificial neural networks method is used to process the experimental data and the across-wind dynamic interference factor (IF_dy) contour map is obtained, which may be used as reference for wind load codes.