Abstract: On the basis of the turbulent boundary layer mean velocity profile over a zero pressure gradient flat plate measured in a water flume using Laser Doppler Velocimetry (LDV), this paper obtains the friction velocity and other boundary layer parameters by using the fit of velocity data to the full boundary layer profile from the wall to the top of the log region. Complementary to the measurements, numerical investigations of the flow field around the flat plate have also been performed. The wall shear stress extrapolated from the profile curve is compared with empirical formula results and CFD results. The data agreement shows that the fit of the LDV measured velocity data to the full boundary layer profile is of high precision for measuring the boundary parameters. Combined with simulation analysis, it can provide the ideal wall shear stress input for the calibration of MEMS wall shear stress sensors.