Aiming at the characteristics of fuzziness and uncertainty in the information of threat factors of air combat, an unmanned combat aerial vehicle (UCAV) threat assessment model is established based on the interval number and fuzzy comprehensive evaluation. The interval number is used to express the weight value of each threat factor and to establish the fuzzy relationship between the enemy unit and the threat factor by fuzzy comprehensive judging method, which can effectively overcome the defect that the threat weight value of the constant vector type determined by the traditional method cannot reflect the ambiguity of the threat degree for the air combat threat, the insufficient uncertainty, and the error that the expert assignment of the expert in the determination weight can be compensated. Simulation results demonstrate the effectiveness of the proposed model.