Discrete Mathematics, edited by Feng Li and others, emphasizes that practice is an application link. In terms of content, the book adds application content and introduces some theories and application examples of knowledge points. Let students realize the practical value of the theory, so as to improve their learning enthusiasm; It reduces the difficulty requirements of theoretical links and some complicated proofs. For the theoretical part, only students are required to understand. In order to make it easier for students to write programs on computers, the chapter "Algorithm Basis" is specially added in this book, which is mainly to let students understand the definition and writing of algorithms and facilitate the practice in the following chapters. Matrix is an important tool to study relational theory and graph theory, so this book adds a brief introduction to matrix and its operation realization method; In each chapter, the algorithm writing part is added, and computer programming exercises are specially set up in the exercises, so that students can experience some knowledge points themselves, deepen their understanding of the theory and improve their interest in learning. Necessary adjustments have been made to the related contents of set and function, reducing the set theory, function definition and general property description, and increasing the set operation and the computer-realized algorithm description of function.