Abstract: Further experimental study has carried out for investigation the properties of the mixture of plaster and diatomaceous earth. It is suggested that the mixture can be considered as a modelling material to simulate marble when the ratio of water to plater is about 1.2 to 2.0, and the ratio of diatomaceous earth to plaster about 0.12 to 0.5. To evaluate the similarity between this mixture and marble , similarity of σ-εγ curve of the mixture are compared with those of marble . Good correlation between the two curves are obtained. It is indicated that in the physico-mechanical model tests for discontinuons media actual states in prototypes can be forthrightly and accurately derived from the information given by model tests, provided such correlations are satisfied.