The effects of free stream turbulence on turbulent boundary layer were calculated using a k-εtwo-equation model. The calculations were performed with respect to velocity profiles on a flat plate, wall shear stress, turbulence energy, integral length scales of turbulence and decay of free stream turbulence, and the results were compared with experimental results. The energy of free stream turbulence and the dissipation values at the leading edge of flat plate were used, as the initial conditions for calculation. These initial values of dissipation were determined from the integral length scales of free stream turbulence at the leading edge. The calculated wall shear stress increased with the free stream turbulence and integral length scales of turbulence. The velocity profiles and turbulence energy agreed well with the experimental results, and the effects of free stream turbulence on the wall shear stress agreed fairly well with those observed in experiments.