In view of the complex and diverse risk factors of military airport fire risk, the risk assessment index and weight calculation method are analyzed and studied. Based on the analysis of the fire risk characteristics of military airport, the indicators of military airport fire prevention are analyzed and the risk assessment index system is established. With traditional weighting ascertaining method, based on the principal component analysis method and AHP, the objective weight and subjective weight are obtained. Based on the idea of maximum variance, acquire the integrated weight by linear combination of objective weight and subjective weight, and verified the weight by test. The results show that the method can greatly reduce the weight variance with practicability and operability.