The attenuation of ultrasonic wave propagation directly affects the descaling efficiency on the surface of heat exchangers. To investigate the attenuation characteristics of ultrasonic waves on the surface of heat exchangers, an experimental setup was designed and constructed, and the experimental measurements revealed the attenuation behavior of ultrasonic waves along the excitation direction, the horizontal direction, and the vertical direction. When ultrasonic waves propagate along the excitation direction, the sound intensity decays exponentially in front of the center of the barrel (x < 50 cm), which follows the theoretical value, while the sound intensity gradually increases behind the center (x > 50 cm). Horizontal to the propagation path in the excitation direction, the sound intensity varies less and is more stable. Furthermore, for a simplified heat exchanger model, the influence of the number of heat exchange tubes and their installation positions on the attenuation of ultrasonic wave propagation was thoroughly analyzed. The effect was found to be limited when the ratio of heat exchange tube to model diameter was ≤1/50 and the spacing was ≥0.195 m. Finally, a model for predicting the attenuation of ultrasonic sound intensity within the heat exchanger was proposed. This research provides valuable insights into the engineering application of ultrasonic descaling technology and the optimal design of heat exchangers.