The question what is the essence of information must be answered for philosophy of information and information science and technology research. However, views on this issue are still divergent. This paper has made the analysis and argumentation about the essence of information by the method of dialectical materialism, and points out that the essence of information are the relations between things and internal things, and this relationship formed information. Due to the connection between the protean and endless things, thus produce the endless, dazzling and variant information. To grasp the essence of information, much attention should be paid to the specific form of information and information processing, the reorganization, transmission, storage, utilization.