Both the U.S. military"s Link16 and TACAN system operate in the L-band and are the primary equipment used in this frequency band. When both systems are distributed and used in the same area, there are clear usage restrictions for compatibility in the U.S. military. This paper analyzes the signal characteristics, spectrum characteristics, technical systems, and other aspects of the two systems, and presents the factors affecting their compatible operation. Through analysis, it is known that following the usage restrictions can ensure the compatibility of Link16 and TACAN system. At the same time, through experimental testing, the impact of different Link16 signals on the TACAN system"s misinterpretation and false responses was simulated, and the test data was analyzed. The research results provide theoretical and experimental support for the compatibility of L-band communication and navigation systems, which can guide the subsequent development of related equipment and systems.