This paper deals with the dynamic response of Very Large Floating Structures (VLFS) in regular waves considering the deflection wave propagation (VLFS-wave) using a simple beam modeling. Firstly, the dispersion relation of VLFS-wave is derived based on the analogy of linear water wave theory, and the relation between the incident wave length and VLFS-wave length is derived. The effects of water depth and rigidity of VLFS on wave length (or dispersion relation) of VLFS-wave are investigated. Next, the reflection wave due to the difference of dispersion relation between the incident wave and VLFS-wave is discussed under some particular assumptions. Finally, a simple method for the response analysis of VLFS is proposed. Using this method, the dynamic response analysis is carried out numerically, and its validity is shown as compared with the results of some other exact analyses. From these results, we can identify the following properties of VLFS : (1) VLFS-wave propagates faster than the incident wave. (2) VLFS-wave length is longer than the incident wave length. (3) When the water depth or the rigidity of VLFS increases, VLFS-wave length also increases. (4) When the incident wave number is sufficiently smaller than the characteristic wave number of VLFS, the wave length or the wave height of VLFS-wave becomes equal to those of the incident wave.