To solve the problem in tactical decision-making of Unmanned Combat Aerial Vehicles (UCAVs) in air combat, and inspired by the dual-process theory in cognitive psychology, we proposed a double-layer tactical decision-making strategy based on Case Based Reasoning (CBR) and MAX-MIN cloud reasoning. Firstly, the experience of pilots was converted into cases to construct a case library, and the first-layer heuristic decision-making based on CBR was achieved by matching the degree of similarity between problem situations and original cases from case libraries. If the degree of similarity was lower than the threshold, it would turn to the second layer, the decision-making based on MAX-MIN cloud reasoning. The characteristic attributes concerning air combating were converted into cloud drops of attributes, then the cloud drops of combating rules was derived with the help of MAX-MIN cloud reasoning algorithm, and furthermore the tactical decision scheme was obtained. The simulation result showed that the double-layer method can implement decision-making effectively, and the time cost for decision-making satisfies the real-time request.