Abstract:In recent years, in order to accelerate the formation of Multi-domain joint battle capability, the US Air Force has applied the concept of " train as you fight " to the tests of new technologies, new tactics and new capabilities. And it innovatively launched a triad of "test flag" series exercises of "orange flag", "emerald flag" and "black flag", which take "test as you fight " as their core concept. They provide an important platform and vanues for accelerating the development of "borne joint" weapons systems and rapidly achieving the “All Domains Operation” capabilities. This paper introduces the fact that the US Air Force has frequently carried out a series of "test flag" exercises in recent years, analyses their theoretical methods and infrastructure capabilities behind the successful implementation of the "test flag" and put forward some suggestions from the aspects of changing ideas, improving mechanisms and integrating resources to promote the development of equipment test and evaluation in China.