Abstract: The assignment method for random parameters of the rock mineral cell unit based on the types and contents of rock minerals is used to assign parameters for the model for two series of mineral cell units. The influences of both rock cell contents and mechanical parameters on the macroscopic parameters of inhomogenous rock materials are studied by numerical experiments. The functional relationship between the mesoscopic and the macroscopic Young's moduli is studied according to the results of numerical experiments. The results indicate that there is a significant linear correlation both between the macroscopic Young's modulus and the mesoscopic Young's modulus of rock mineral cell units and the contents of mineral cell. In other words, for the model for inhomogenous rock based on the assignment method for random parameters of the rock mineral cell units, there is a significant linear correlation between the macroscopic and the mesoscopic mechanical parameters. The macroscopic mechanical parameter can be expressed by the mathematical expectation value or weighted average of the mesoscopic mechanical parameters.