The geophysical parameters of the carbonate karst reservoir has a strong inhomogeneity and intensive spatial variation,which is difficult to be depicted by the conventional method used in layered medium situation.In this paper,the relation between the character of the karst reservoir and the parameters of the random model is discussed and the random medium model is established to describe the statistical character of the geophysical parameters distribution.The introduction of the random medium method provides a more effective approach for the research of the seismic reflection of the carbonate karst reservoir.