In this study, a large eddy simulation is used to calculate three-dimensional high Reynolds number free jet flow (Re=1.0x10(4)). The fifth-order upwind finite difference scheme and second-order Runge-Kutta method are used for the convective terms and the time developing term, respectively. For the other terms in the basic equations, a second-order central finite difference scheme is adapted. Since the nozzle aspect ratio is 10.0 (limitless length slit is simulated using periodic boundary condition), and the flow field ranges from the nozzle exit to the developed turbulent region, it seems that this is the largest-scale numerical analysis of the jet reported to date. The calculation is from early unsteady-state (air starts at the nozzle outlet) to steady-state (turbulence characteristics became stationary), considering turbulence unsteady motion. Calculated results are in fairly good agreement with experimental data for turbulent characteristics and power spectra. Simulation results are visualized by iso-vorticity and iso-turbulence enegy contour plots which show structures of turbulence jet. It may be concluded that the large eddy simulation describes well the turbulence characteristics in a high Reynolds number free jet which are important for various engineering systems.