Abstract: Numerical simulation was conducted to investigate the wind pressure distributions on the surface of a spherical tall building with and without curved annexes. Significant effects induced by the annex on the wind loads on the main tall building were observed. Due to the existence of the annex the area of positive pressures on the windward and leeward surface of the spherical building was reduced, and the maximum positive pressure also had a slight decrease. The absolute values of the maximum negative pressure on the sideward and top surface of the building increased to a relatively large degree. The total wind loads on the building tended to become larger and the pressure distribution tended to be more non-uniform. Symmetrical vortex street in the leeward area of the spherical building was observed due to the interference effects of the annex. Based on the analysis of wind pressure distributions under different wind directions, the wind-pressure coefficient variation curves on the most unfavorable sections under the most unfavorable wind directions are presented.