Ultra-thin silver films were deposited by thermal evaporation, and the dielectric functions of samples were simulated using Drude-Lorentz oscillators. When s-polarized incident light from the BK7 glass into thin silver film at 45° angle using attenuated total reflection (ATR) mode, we experimental observed that the reflection reach a minimum of 1.87% at 520 nm for thickness of d~6.3 nm silver film, and it reach a minimum of 10.1% at 500 nm for thickness of d~4.1 nm. Moreover, we simulated the absorption changes with incident angles at 520 nm for both p-polarized (TM wave) and s-polarized (TE wave) light using transfer matrix theory, and calculated the electric field distributions. The absorption as a function of incident angles of TM wave and TE wave showed different characteristics under ATR mode, TE wave reached the maximum absorption around the critical angle θc~41.1°, while TM wave reached the minimum absorption.