The flow mechanism of flowing over two circular cylinders in tandem arrangements is numerically investigated. First, the unsteady incompressible NavierStokes equation is solved using twodimensional large eddy simulation (LES) model in order to capture the flow instantaneous source data. Then both the FWH equation and its integral solutions based on Lighthill’s acoustic analogy are employed to compute the noise generated by fluid flow. Different flow velocity, circle cylinder diameter and spacing ratios are compared. The result shows that the SPL augments with the increase of flow velocity or circle cylinder diameter. The frequency of vortices shedding is raised with the increase of flow velocity. Different spacing ratios impact the vortices shedding at a certain extent, and as a result impact the acoustic noise. There is the largest SPL near the critical spacing and the direction of acoustic fields is obvious.