This book presents dynamic response, vibration characteristics, and nonlinear behavior of complex oil and gas well string by using a combination of theoretical methods, numerical simulation, and experimental analysis. It lays both theoretical and experimental foundation for the design of oil and gas well string parameters. The theoretical methods involved mainly include Hamilton's principle, finite element method, and energy method, while experimental methods involved include similarity principle, vibration testing method, and modal analysis method. It is a valuable reference for both scholars and practitioners working in the fields of petroleum, mining, and geological research, as well as research institutes related to oil and gas resource exploration.