Abstract:The impact of changes in the relative height of a interfering building on main building layer lift force coefficients and lift force power spectrum was studied by rigid model pressure tests. Three side by side positions,five tandem positions and three oblique positions were considered. The results show that in the side by side cases the greater the relative height, the bigger the mean layer lift force coefficients, so as the affected height of lift force power spectrum. In the tandem cases, the relative height of the interfering building has little effect on the mean layer lift force coefficients, but it has great impact on the root mean square(RMS) of layer lift force coefficients. When the height of the interfering building exceeds that of the main building, the impact on lift force power spectrum is great, especially in the top area. In the oblique cases, the across wind spacing ratio plays a leading role in the interference law.