ABSTRACT: The numerical modelling techniques provide quite useful insights about how the interaction between engineeringstructures and host rocks develop. On the other hand, the representation of the real rock domain depends on thereliability of the numerical model used. For this reason, micro parameters of a model must be calibrated accuratelyand 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 parameteris analysed individually by performing a number of uniaxial compressive, uniaxial tensile, and triaxial compressivetest simulations through Yade open source DEM code. Obtained results show that the uniaxial compressive strengthof the rock (UCS) mostly depends on micro-cohesion while the uniaxial tensile rock strength (UTS) primarilydepends 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 isincreasing with an increase in micro-internal friction angle and the strength ratio (UCS/UTS) is arranged based onthe coordination number assigned at the beginning of the simulation. This study presents the constituents of strengthand deformation properties of a rock according to the interaction between the model parameters. The results provideapplicable, practical and guiding insights in terms of developing numerical models which predict the rock behaviorsbefore the construction of engineering structures