The work aims to investigate physical characteristics and secondary electron emission (SEE) characteristics of titanium nitride (TiN) thin film in vacuum, and verify its good conductivity and relatively low secondary electron yield (SEY) as well as its well application in the field of treating the surfaces of the space high power microwave component. Radio frequency magnetron sputtering was adopted to prepare the TiN thin films on the substrates of monocrystal silicon sheets and glass sheets. Atomic ratio of nitrogen (N) and titanium (Ti) was controlled by adjusting the gas flow ratio of N2 and Ar during sputtering. SEM was utilized to characterize the surface morphology and thickness of the TiN films. The SEE research platform with ultrahigh vacuum was used to characterize the SEE characteristic of the TiN films. The contents of N and Ti elements in thin films could be effectively controlled by adjusting the gas flow ratio of N2 and Ar during sputtering and then the crystallization mode and other physical properties of titanium nitride thin film were changed. When the gas flow ratio of N2 and Ar was 10:15, atomic ratio of N and Ti in the film was about 1:1. Through the resistivity test, the closer the atomic ratio of N and Ti in the film got to 1:1, the lower the resistivity of film was. From SEY test results, the lowest peak value of SEY in TiN films was about 1.46 and lower than that of SEY in flat gold film (~1.8) and flat silver film (~2.2). TiN thin films possess good conductivity and lower SEY as well as favorable stability in vacuum environment. Therefore, TiN thin films can effectively lower the risk of multipactor without influencing the surface loss of microwave components.