///The problem that it is difficult to identify the structure of thin interbedded reservoir is studied in the paper. After deep studying, the authors achieved the further discovery that those parameters which can be used to describe the character of amplitude spectrum, such as the period and number of main lobe, the period and number of side lobe, the amplitude at the points of f=0 and f=fN, are the important parameters to ascertain geologic structure of thin layer, thin interbedded layer, thin and thick interbedded layer. If the character of thin layer is not very complex and high and low frequency components are not lost during acquisition and previous processing, those geologic structures such as thin layer or thin interbedded layer can be identified and predicted by the structural character parameters such as amplitude spectrum of record in which the influence from wavelet is cut completely or partly, or even logarithm spectrum, etc.