Based on the author's many years of research, this book expands and complements the latest research results in this field. It introduces in detail the basic principle, growth technology, development status and application trend of GaN single crystal material growth. The author team adopts an open and learning attitude and discusses the future development of GaN material growth and device applications with colleagues in the field. It is hoped that the publication of this book can present the frontier development status and prospect of GaN material growth and application to personnel in related fields, hoping to make readers more thoughtful and generate positive innovation points.