The electromechanical actuator (EMA) has been widely applied in the aerospace field due to its high reliability and maintainability. As a key component of the flight control system of an aerospace vehicle, the performance of the electromechanical actuator directly affects the function of the entire vehicle. In this paper, detailed dynamic modeling of the servo controller, motor, and mechanical transmission mechanism is conducted considering the elastic stiffness of various mechanical components and the nonlinearity of multi-link clearances inside the actuator. The multidisciplinary coupled dynamic model of the electromechanical actuator-fin system is established through a modular modeling method to relieve ground testing efforts. Then, a series of ground tests are carried out based on the virtual prototype in digital space. In these virtual tests, simulation analysis of electromechanical actuator performance under different operating conditions enables the rapid acquisition of various performance indicators of the system. The test results are compared and analyzed with the performance requirements to verify that the system meets the requirements. The results show that the multidisciplinary coupled dynamics model proposed in this paper can quickly obtain the required performance parameters and give evaluated results. Compared with traditional ground testing, the virtual ground testing method significantly simplifies the test process, reduces the test cost and improves efficiency. In addition, this study lays the foundation for the fully digital design and optimization of high-performance electromechanical actuator systems.