The microwave landing system (MLS) signal source needed to measure a large amount of parameters quantitatively, and the conventional measurement methods needed a large number of instruments and the connection was complex which led to the great limitation of measurement efficiency and accuracy. The development of intelligent instruments provided the foundation of automatic measurement. Based on the analysis of the test characteristics of the signal source state parameters of MLS, the development of automatic test system was completed on the MATLAB platform Practical testing results indicated that the automatic test system had the characteristics of high precision and high efficiency in the process of measuring the state parameters of the MLS signal source, and this system could realize the atomization of the measurement.