Large eddy simulation was applied to simulate the 3-D compressible flow past one and two wall-mounted rectangle cylinders, respectively.The dynamic subgrid stress model was employed to approximate the subgrid scale effects.Flow past over one single wall-mounted cylinder was used as an example to validate our code, and two wall-mounted cylinders is chosen for investigating the variation of flow fields and drag coefficients under different heights of two cylinders.Our numerical results show that, with certain ratio of two cylinder height, their drag coefficient can be improved, this may guide the arrangement of buildings for practical construction industry.