Aircraft operational readiness is one of the important indicators of military aircraft fighting capacity and equipment performance, which is closely associated with the reliability, testability, maintainability and supportability of the aircraft. Based on the analysis and existing research about the model of operational readiness of aircraft, the parameter value of model on evaluating operational readiness is overestimated. Because the assumption of the model is that the aircraft is always reliable in the initial state before performing a mission each time, and it did not take account of the fact that broken-down aircraft fail to repair during the interval time of mission and need to be continued for maintenance. In addition, the above-mentioned models are used to evaluate the operational readiness which is essentially a static index for now or at some point in the past, which cannot be used to evaluate the operational readiness at some point in the future and predict the trends that the operational readiness changes over time. Aiming at these problems, on the basis of the basic model of operational readiness in this paper, the model of operational readiness is modified. Not only consider the operational readiness of aircraft at a certain moment is affected by the state of aircraft at previous moment, but also intuitively present the changing trends of operational readiness in the mission profile. By comprehensive considering the state of the aircraft, the reformative model is more in line with the meaning of operational readiness. Finally, the validity and practicality of the research were demonstrated through a case and the final conclusion is given.