At present, major websites and major game companies are recruiting digital designers one after another, major universities have also set up video game design majors, and traditional art departments have gradually got their hands on CG (computer graphics); The market and education are full of demand for CG, which fully shows that CG has gradually become the mainstream force of 2D and 3D design. Chapter 1 of Digital Design: Principles and Practice (fourth edition) gives some basic definitions and rules in digital design, whether they are important or not. The second chapter introduces the binary number system and coding. The third chapter describes the operation of digital circuits, focusing on the external electrical characteristics of logic devices. The fourth chapter expounds the design principle of combinational logic, including the analysis, synthesis and minimization of switch algebra and combinational circuits. The fifth chapter gives the basic introduction of the design based on hardware description language, and then gives the learning guidance of three basic hardware description languages ABEL, VHDL and Verilog. Chapter 6 first discusses the document standard of digital system, which is usually the most important part when starting the actual circuit design. Chapter 7 describes the design principle of sequential logic, starting with the introduction of latches and flip-flops. Chapter 8 introduces the design practice of synchronous sequential circuits. Chapter 9 introduces the related knowledge of memory devices, CPLD and FPGA. Most chapters of digital design include references, exercises and exercises.