The vigorous development of information science and information technology seems inappropriate, but the basic definition and essential concept of information have not been recognized, clear and scientific. At present, there are more than 100 discussions about the definition and concept of information. Although there are still great differences and even contradictions between the definitions and concepts of information put forward by people from different fields and angles, and new viewpoints and opinions are constantly put forward, the understanding of information has gradually deepened, and the long-term debate itself has also illustrated the profoundness and complexity of the concept of information. In recent years, some scholars have put forward complete information theory, unified information theory, general informatics and generalized information theory, all of which are trying to reveal the essence of information concept in a wider field and at a deeper level. "What is information" has been included in a book compiled by China Academy of Sciences, which is one of the 100 difficult problems. With the efforts of the vast number of scientific workers, I believe that this scientific problem will eventually be better solved. A clear understanding of the concept of information essence will further promote the development of information science.