A two-dimensional model of staggered tube banks of the bristle pack with different pitch ratios was solved by computational fluid dynamics (CFD). The pressure distribution along the gap centerlines and bristle surfaces were studied for different upstream pressure from 0.2 to 0.6MPa and models. The results show that the pressure is exponentially rather than strictly linearly decreasing distributed inside the bristle pack. The pressure distribution is symmetry about the circle's horizontal line. The most obvious pressure drop occurred from about 60 degrees to 90 degrees. There is no stationary state reached between the kinetic energy and the static pressure when the upstream is larger than 0.3MPa.