Fidelity reflects the consistency between flight simulator and real aircraft characteristics. Objective evaluation is an engineering method to evaluate the fidelity by comparing the simulator with the actual behavior of the system. Flight simulators are divided into engineering simulators and training simulators. The configuration of the training simulator used for flight training rarely changes, and its test cases are guided by airworthiness standards. However, the engineering simulator used for design verification often needs to be upgraded or changed according to the aircraft development progress, and its test cases will also change. Under the background of the increasingly complex technology of civil aircraft, it is urgent to develop an efficient method to objectively evaluate the fidelity of this type of simulator. Under the background of the increasingly complex technology of civil aircraft, it is urgent to carry out the objective evaluation and test of the fidelity of this type of simulator. Based on the experimental framework, system entity structure and model base framework, this paper proposes a model-based testing method. In the application of objective evaluation of engineering simulator, this method can realize the automatic generation and execution of test cases, improve the work efficiency, and have flexibility and adaptability in the process. It is helpful to the finalization or certification of aircraft under development.