Abstract: Based on electromagnetic similitude theory, the scale model of an airport environment equipped with a microwave landing system (MLS) was set up to simulate the propagation of the navigation signal transmitted by the MLS according to the propagation of the laser in the scale model of the airport. This simulation system used the MATLAB/RTW rapid prototyping target (i.e. xPC target) to carry out the real-time simulation of the airborne receiver signal processing. The critical technologies of the optical subsystem for this simulation system were researched. The azimuth error curve of the flight test of an airport environment in U.S. was obtained, and the experimental results agreed with flight test results, which proved the effectiveness of the MLS simulation test.