A computation procedure (CFD-Fluent 6.2) for two-dimensional fluid flow is applied to predict the pressure drop and heat transfer characteristics of laminar and turbulent flow over staggered flat-tube bank. Effect of aspect ratio (H/D/L/D) on pressure drop, temperature, and velocity contour for laminar and turbulent flow over staggered flat-tube bank is studied. The theoretical results of the present models are compared with previously published experimental data of different authors. Satisfactory agreement is demonstrated. Also, the comparison between the present study and others' analytical methods for the Re number with Nu number is done. The results show that the Reynolds number increases the maximum velocity in the passage between the upper and lower tubes' increases. The comparisons show a fair agreement, especially in the turbulent flow region. The good agreement of the data of this work with these recommended analytical methods validates the current study.