Abstract: Based on the frequency spectrum of pressure fluctuation of gas-solid two-phase flow and tube cross-section image reconstruction algorithm, as well as improved code with fluctation-tomography fuzzy discriminant analysis, uniform flow and stratified flow and the flow at which blockage of tube might happen were effectively detected by some experiments. These tomographic results demonstrate,that it is feasible to detect the flow pattern in horizontal tube by use of pressure fluctuation spectrum signature and tube cross-section image reconstruction algorithm with fluctuation-tomography fuzzy discriminant analysis.