The apparent behavior of composites is primarily determined by the respective properties of its constituents. However, the architecture of microstructure, i.e., volume fraction, size, shape, orientation and arrangement geometries of constituents, affect the stress and strain portioning of the constituents. The design of high performance, tailor made composite materials can be realized by optimizing the microstructural features. A numerical method is presented in this paper for calculation of the elastic behavior of particulate reinforced composites having a continuous metal matrix including ceramic particulates. The effects of the arrangement and orientation of ceramic particulates on the stiffness tensor of metal matrix composites were estimated. The numerical method presented can consider the arrangement and orientation effects of the reinforcement via a simple parameter named as the geometrical factor (Gf). In order to determine the geometrical factor of Gf, the projection areas of reinforcement and reinforcement embedded RVE are calculated with respect to loading direction. The geometrical factor of Gf was changed between the Gf value of the reinforcement and RVE in the implementation of numerical iterations in order to simulate the effects of the microstructural architecture. Hence, the effects of orientation and arrangement can be considered. Voronoi tessellations including a complete reinforcement were used as RVE. The Gf value of RVE was calculated with respect to the loading direction. The estimation of numerical calculations were in very good agreement with finite element method findings. An important advantage of numerical method proposed in this work is to allow the systematic and parametric investigation of the effects of the microstructure architecture on the elastic behavior of particulate composites. Further, the proposed numerical calculation approach is easy to implement and gives quick results.