Abstract: A new method for calculating three-dimensional compressible laminar. and turbulent boundary layers on practical wings is described in this paper. In the method, a nonorthogonal coordinate system proposed by Ce-beci is used, and a secondary coordinate transformation is suggested to overcome difficulties arised when negative transverse velocities appear locally. Several computational results for Lockheed C-5A aircraft wing and F-8 supercritical wing are given in the paper, and comparisons with other methods and with experimental data are made as far as possible.