Abstract: This paper reviews firstly the history and applications of frustrated total internal reflection （FTIR）. A simple description of FTIR is presented and the formula of evanescent wave＇ s transmission is obtained. A simple experiment apparatus is established to study the relation between the transmission in FTIR and the thickness of air film, the polarization direction. The experimental results are in agreement with the theoretical analysis quantitatively.

Key words: FTIR, transmission, light polarization