Abstract: The strength and deformation characteristics of coarse-grained soil directly affect the deformation law of rockfill dams. In order to study the deformation mechanism of coarse-grained soil from the microscopic level, the discrete element method is widely used as an effective means to simulate the mechanical properties of coarse-grained soil. The particle strength and elastic mechanics are very important for the establishment of the discrete element method model. How to obtain the distribution law of these parameters is a very necessary work at present. The uniaxial compression tests are carried out on a series of Dalian limestone particles with different sizes, and the distribution law of mechanical parameters including the strength and elastic modulus is determined by characterizing the force-displacement experimental curves. The statistical results show that compared with the Weibull distribution and Logistic distribution, the Lognormal distribution has the best statistical effect on particle strength and elastic modulus, and the mean values of both two parameters decrease with the increase of particle size. Then, based on the size correlation of parameters, empirical models for size effect suitable for limestone are established. Finally, the stiffness of limestone particles is discussed preliminarily. The experimental results show that the stiffness of limestone particles has obvious nonlinear characteristics. These results may provide a reference and support for the calibration of microscopic parameters in the numerical simulation of the discrete element method for coarse-grained soil.