In the vibration of the horn, the damping characteristics of the ultrasonic horn and its coupling with the bolt / tool head will lead to obvious temperature rise. In order to analyze the temperature rise characteristic and explore its influence on the vibration stability of the ultrasonic horn, the total power density and temperature distribution of the longitudinal vibration horn were obtained by numerical simulation. The theoretical temperature rise of the ultrasonic horn was verified by infrared thermal imaging test, and the influence of bolts and tool heads of different materials on the temperature rise was analyzed. Combining the numerical modal analysis and experimental analysis, the influence of temperature rise on the resonant frequency and amplitude of the horn was further discussed. The results show that the temperature rise tends to be balanced during continuous operation of the ultrasonic horn, and the equilibrium point depends on the bolt material, horn material and environmental factors. For low damping TC4 horns, energy loss at bolt is the main heat source, of which 45 steel bolts generate 97.7% of the heat, while TC4 bolts and tool heads can significantly reduce the temperature rise. At the same time, it is found that the resonance frequency of the ultrasonic horn is linearly negatively correlated with the temperature rise. The amplitude is reduced due to the temperature rise, and both of them are stable at the equilibrium temperature point.