Combat effectiveness assessment plays a crucial role in modern military operations, and its effectiveness directly affects combat

efficiency, resource allocation and decision support. Firstly, the phase angle in quantum interference theory is introduced as the

interference adjustment factor of grey correlation model, in which the traditional combat indicator system is reconstructed and

optimized. Secondly, the properties and theorems of the grey correlation model after the introduction of quantum interference are

analysed, and based on the quantum entanglement characteristics of UAV combat, its combat effectiveness is quantitatively evaluated through the quantum interference-grey correlation model. Finally, the effectiveness of this study is illustrated by a case study of UAV cluster formation programme. The results of the study show that the index assessment method not only improves the accuracy of combat effectiveness assessment, but also provides powerful support for actual military decision-making, demonstrating a wide range of application potential and important practical value.