The noise tests of the actual sound barrier and the scale model sound barrier are completed using the HEAD acoustics multi-channel noise test and analysis system based on similarity theory and model test knowledge. Comparison and analysis of the test results show that the scale model sound barrier has good consistency with the actual sound barrier in the frequency band from 125 to 5000Hz; the sound barriers have excellent noise reduction behavior for middle and high frequency noise, but the effect for low frequency is not good. The experiment results provide a high application value and practical significance for the future design of the sound barriers. PRESENTATION OF QUESTION The experiences and lessons of urbanization process in developed countries tell us that housing, environment and traffic are the three elements that impact the urban development and the most important element is the traffic. With the dramatic increase of urban population and the rapid development of automobile industry in China, urban road traffic is overcrowded. In particular, the transportation problems have become increasingly sharp in the city with a population of more than one million. In the case of heavy traffic on the ground, building overpasses and viaducts can effectively evacuate passenger flow. But the vehicles running on the overpasses and viaducts make noise pollution more serious due to the radiated noise from viaducts. At present, traffic noise has become an important factor that restricts the improvement of the quality of urban living environment. With the development of environmental treatment technologies and the continuous improvement of people's awareness of environmental protection, some studies and explorations of sound barriers have been carried out in our country. The installation of sound barriers has