Engineered resilient system (ERS) is a future defense system development strategy proposed by the United States department of defense (DOD) in response to increasingly uncertain tasks and environments, which brings new challenges to the engineering practice and theory of system resilience. Firstly, this paper introduces the background of ERS, focusing on the perspectives of the DOD on ERS, which include the key attri-butes of ERS, the relationship between ERS and legacy system, the factors considered in ERS design and the relationship between ERS and system engineering. Secondly, the progress of ERS projects prioritized by the DOD is researched. Meanwhile, a literature review on system resilience theory is conducted, including system resilience definitions, assessment and analysis methods, in order to have a more comprehensive understanding of ERS. Finally, on the basis of the research on ERS, the challenges faced by ERS and system resilience theory are discussed theoretically and practically.