The possibility of using protein calibration data for rapid analysis of ultrafiltration membrane structure is discussed. It is shown that structure analysis based oil calibration data gives the possibility of determining the mean membrane pore radius, and the view of distribution of pores by size, to reveal and to asses the microscopic membrane defectness, to estimate the thickness of selective layer, and also to correlate the structure of investigated membrane with that of the principal serial ultra-filters. Beside this, the use of permeability data obtained during protein calibration gives the possibility to assess the hydrophilicity of membrane investigated. However, the principal advantage of this method is high productivity and the possibility to perform the analysis with the use of the simplest Ultrafiltration and gel chromatographic equipment. The examples of the use of membrane structure analysis in the Course of development of composite polysulphoamide membranes and track-etched ultrafilters are given.