The purpose of this paper is to investigate the highly complex interaction between turbulent flow and deep-sea marina structure using a commercial CFD code (FLUENT 6.2) with Large Eddy Simulation (LES) approach. A series of three-dimensional LES of wake flows past overlapping cylinder of finite height are carried out with a range of Reynolds number 1.0×10^4 ~ 1.0×10^5. Three different heights of circular mud mat having a fixed diameter are simulated to study the effect of the height of mud mat on turbulent flow field around this kind of bluff body. The complex separated flow structures and wake properties are simulateed and discussed.