Abstract: The wind load of three steel chimneys in a regular triangle arrangement is numerically investigated. The spacing ratios are in the range of 2.4≤L/D≤4.8，where L is the distance between the centers of adjacent chimneys, D is the diameter of a single chimney. The numerical simulation results show that in small spacing ratio, the mean drag coefficient of an upstream chimney is smaller than that of a single chimney, and that the mean drag coefficients of two downstream chimneys are slightly bigger than that of a single chimney. When spacing ratio is small, there are lift forces acting on two downstream chimneys. The lift forces are equal to each other but act in an opposite direction.