© 2021, TMMOB Chamber of Geological Engineers. All rights reserved.The numerical modelling techniques provide quite useful insights about how the interaction between engineering structures and host rocks develop. On the other hand, the representation of the real rock domain depends on the reliability of the numerical model used. For this reason, micro parameters of a model must be calibrated accurately and model results must be irrespective of the model resolution and/or dimension. Recently, the discrete element method (DEM) is mostly used to determine the mechanical behaviors of the complex solid materials such as rocks. The purpose of this study is to investigate the effects of required micro parameters for developing a numerical model-based on such method-on macro mechanical properties and deformation behaviors of a rock. Every micro parameter is analysed individually by performing a number of uniaxial compressive, uniaxial tensile, and triaxial compressive test simulations through Yade open source DEM code. Obtained results show that the uniaxial compressive strength of the rock (UCS) mostly depends on micro-cohesion while the uniaxial tensile rock strength (UTS) primarily depends on tensile strength between the particles. Furthermore, both strength properties are in relation to the microelastic modulus and stiffness ratio. The deformation properties such as Young’s modulus (E) and Poisson’s ratio (ν) are directly controlled by the micro-elastic modulus and stiffness ratio. The slope of the rock failure envelope is increasing with an increase in micro-internal friction angle and the strength ratio (UCS/UTS) is arranged based on the coordination number assigned at the beginning of the simulation. This study presents the constituents of strength and deformation properties of a rock according to the interaction between the model parameters. The results provide applicable, practical and guiding insights in terms of developing numerical models which predict the rock behaviors before the construction of engineering structures.