Digital twins， are characterized by virtual-real integration and real-time interaction， provide new methods for operational experiments of air and missile defense. Digital twin operational experiment system architecture of joint air and missile defense is designed to address the application of digital twin technology in related experiments. This paper studies the concept of digital twins and analyzes the system architecture requirements of joint air and missile defense operational experiments. It elaborates on the three architectural design principles： data support， model-driven， and application-oriented， proposes a three-layer architecture design： data aggregation， dynamic modeling， and simulation application， and discusses three application modes： independent， interactive， and hybrid. The digital twin-empowered experiment process offers complete and highly realistic operational elements， real-time interaction between virtual and real， and efficient and credible evaluation， effectively supporting the systematic solution of related experimental problems.