Abstract: An extention of the analytical mean stream line method to cascades along an arbitrary stream filament of revolution is presented, the accuracy of solution from this method is higher than the existing numerically computing method as well as the time needed for one complete calculation is shorter. A calculated example and some recommended design variables of axial-flow turbomachine cascades are given. According to the analysis of the order of magnitude of each term in the equations, it is found that the straight cascade assumption is not so suitable not only to the axial-flow long blade stages, but also to some short blade stages with a converging annular passage and this unsuitability is more serious to the compressor stages. The calculating equations and tables of functions of this paper are also applicable to radial and mixed flow turbomachine cascades.