Despite the importance of identifying industry-wide impact of technology fusion, there are few studies to analyze interdisciplinary trends of technology convergence from an industry-wide perspective. This paper, therefore, presents a procedural method to analyze trends of industry-wide technology fusion by measuring knowledge flows of patents. The method constructs a technological knowledge flow matrix that represents knowledge flows among technology classes, and then extends it to an industry-wide knowledge flow matrix by exploiting the concordance between technology classes and industrial sectors. By computing assessment indicators of technology fusion regarding industrial sectors of a specific technology area, the method outputs a visual map that shows trends of industrial technology fusion. The presented method is illustrated using patents related to the new and renewable energy-based railway technology. We expect that the method will be incorporated into the R&D planning processes to assist R&D planners to initiate new R&D projects with a proper direction. Under these directions, the R&D projects can create new inventions by converging prominent technologies beyond industrial boundaries. Further, the method has the potential to become a basis of systematic support systems for technology experts to conduct knowledge-intensive technology planning activities. (C) 2013 Elsevier Ltd. All rights reserved.