H index is an index designed by physicist Hirsch of the University of California in 2005, which is used to evaluate researchers' personal scientific achievements. If at least H papers published by a researcher are cited at least H times in a certain period of time, its H index is equal to H. Compared with traditional single-dimensional scientific research evaluation indicators such as papers or citations, the biggest feature of H index is to skillfully bind papers and citations together, so that the cited frequency and the number of papers are balanced, which provides a new idea for evaluating scientific research performance. Initially, the H index was mainly used to evaluate the personal achievements of researchers. With the continuous popularization of H index in practical application, H index has been extended to different evaluation objects such as fields, periodicals, institutions and countries. Web of Science can now directly provide the H index of the author's articles on SCI. Log in, search with the author's name, click "Create Reference Report" in the upper right corner of the search results page, and find the H index in the upper right corner of the display page.