Scratch is a teenager-oriented programming tool designed and developed by the Massachusetts Institute of Technology (MIT). By dragging corresponding blocks with the mouse, users can compose scripts with different functions. Many children fall in love with this colorful software at first sight. This book is based on the demonstration of Scratch 3.0, and has 13 chapters. Chapter 0 is the preparation for learning; Chapters 1-9 are the basic contents, with each chapter introducing a separate module that can be read independently or sequentially; Chapters 10-12 are the advanced contents, including both algorithm cases and game cases. The book is accompanied by videos meticulously prepared and can be watched by scanning the QR codes with mobile phones.