This book gives a comprehensive introduction to the new geophysical detection theories, methods and technologies of tunnel engineering under complex geological conditions and environments. It mainly focuses on the application of 3D seismic technique, 3D high-power resistivity sounding, and 3D GPR, etc. There are 7 chapters in the book. Chapter 1 introduces the state of the art and developing trends of geophysical detection technologies for tunnel engineering. Chapter 2 analyzes the complex geological conditions and environments for tunnel construction and the latest geophysical detection technologies. Chapter 3 to Chapter 7 systematically elaborate on the 3D seismic techniques, 3D detection technologies for water content in tunnel surrounding rocks, 3D detection technologies for side/back slope, 3D detection technologies for shield tunneling, and 3D detection technologies for collapse treatment of tunnel construction. The book presents numerous case studies to illustrate the applications of these technologies.