Abstract: The radio navigation system is primary facility of aircraft and fidelity of simulation affects the training effect directly. Firstly, total simulation framework is established, constitution and design of software and hardware system is discussed in detail. Secondly, simulation methods of various navigation devices are put forward. Lastly, simulation model of direction finder error is designed based on the analysis of direction finder error arisen reason and multifactors of environment are considered. Simulation precision of radio navigation is improved. At present, the system is used in flight simulation and works well.