Terahertz (THz) waves have attractive prospect in application,because of its many unique properties. However,due to the intense absorption from vapor,the transmitting distance of THz waves in air is very limited, and its application is greatly restricted.Terahertz enhanced acoustics (TEA) phe nomenon provides an effective way for detecting THz waves remotely,through combining tactfully THz waves with photoacoustic signals. The paper studies preliminary the physical process and inner mechanism in TEA,an d acquires the quantitative relationship between THz emission and increase of photoacoustic-signal′s ampli tude by deducing theoretical model about TEA approximatively.