In view of the current operational effectiveness evaluation of missile weapon systems,there are problems such as large hierarchical span,complex basic data,and many structural uncertain factors.Based on the mission and method framework,constructs an antiship missile combat index system,and combines the observe,orient,decide,act (OODA) combat loop idea to construct a system combat network model.Using the improved information entropy method,a scientific and accurate combat effectiveness evaluation method is proposed.The missile combat effectiveness is evaluated through specific examples,and the system contribution rate of the new antiship missile is calculated to be 16.2%,which verifies the feasibility of this method.