With the complexity of the scientific system, many social problems and scientific research programs cannot be solved by one discipline, and interdisciplinary research has become an indispensable model of modern science. It is of great significance for the development of interdisciplinary research to explore the importance and evolution trend of interdisciplinary research. Based on over 50-year high-cited papers (top 1%) of the Web of Science, this study uses the third biodiversity index, the Leinster-Cobbold diversity indices (LCDiv), and interdisciplinary property indices, namely Variety, Balance and Disparity, to analyze the evolutionary trends of interdisciplinary research. The study shows that interdisciplinary research is becoming more important in science, variety shows an increasing trend, balance shows a decreasing trend and disparity shows an increasing trend for most disciplines. The analysis also shows that the interdisciplinary characteristics of highly cited papers, namely high variety, low balance and high disparity, is becoming more and more evident over time.