Abstract: Particle crushing in geomaterials, e.g., soils or rock, is a theme of global focus due to its significant effect on the behavior of geomaterials. In order to investigate the intrinsic connection between the macroscopic and microscopic mechanical behavior of rock particle crushing, a number of uniaxial compression numerical tests of rock particles were carried out based on the discrete element method to investigate the macroscopic mechanical behavior of rock particle compression under different conditions(e.g., loading rate, particle size, sub-particle bonding strength, and single-particle porosity). In this study, the rock particle crushing strength is revealed to increase with increasing loading rate or sub-particle bonding strength, but to decrease with increasing particle size or porosity. The macro-micromechanical behavior and mechanism of rock particle crushing were also investigated comprehensively by establishing the intrinsic linkage between the macro-mechanical behavior(e.g., stress-strain behavior and particle crushing phenomenon) and micro-mechanism(e.g., force-chain evolution, bond breakage, and micro-crack development) of rock particle crushing. In addition, by studying the energy conversion in the compression process of rock particles, it was found that the boundary energy was transformed into strain energy and dissipation energy during the rock particle crushing process with bond breakage and crack development. This study is valuable and helpful in understanding the macro and micromechanical behavior of rock particle crushing, which is of great significance in guiding engineering practice.