To accurately assess the operational effectiveness of the unmanned air vehicle (UAV), based on the dynamic analysis of the UAV operations against the sea assault, the article analyzes the main factors that affect combat effectiveness. Combined the AHP, an operational efficiency evaluation index system for UAV is constructed. The paper uses expert scoring method to give the weight and evaluation of operational effectiveness evaluation indicators, adopts the cloud synthesis model to achieve the combination of qualitative and quantitative combat effectiveness evaluation indicators, and uses the operational rules of the normal cloud model to draw the comprehensive effectiveness cloud of UAV. Simulation analysis results prove the validity and feasibility of this model.