Abstract: The structural problem is a key and difficult research topic in soil mechanics. For the structural analysis of static soil mass, some literatures have made a preliminary discussion. But for rock or soil that is made up of large quantities of grains, the diversity and complexity of its structural morphology have been widely acknowledged. However, the understanding of the features of rock and soil mass of variable morphology is still obscure so far. To determine the effect of structural morphology of rock and soil mass on its properties, we establish an orthogonal equal-cell soil mass model to study the critical stiffness features of the soil mass. The presence of pores and holes of different morphologies is considered when observing the changes of some important performance indexes of the soil mass. The analysis of the orthogonal equal-cell model indicates that the structural performance of rock and soil mass depends on their porosity, pore distribution, pore morphology and pore directionality. The larger pore area (volume) exerts a greater effect on structural performance. At a given porosity, the more scattered, that is, the larger the quantity of the pores, and the larger the pore surface area, the greater the effect on structural performance (stiffness) will be.