Compared with the civil aircraft, the restoring, maintaining and improving based on the combat effectiveness must always be taken as the fundamental purpose, and simultaneously, the seeking for the best economy must also be taken into consideration in the whole process of the maintenance and the support for the military aircraft. In this paper, a generalized model of combat effectiveness is established firstly based on the definition of combat effectiveness, and a concept named Combat Effectiveness Based Maintenance and Support (CEBM&S) is put forward. The connotation of the CEBM&S is expounded, and an application process of the CEBM&S is proposed, and an example is given. Finally, there are two key problems of the CEBM&S to be discussed. By applying the CEBM&S, the relationship between the combat effectiveness and the maintenance & support activities can be quantified by a mathematical model, and then the combat effectiveness can be maximized by optimizing the maintenance and support process.