Abstract: The discrete element method (DEM) plays an important role in studying the micro-mechanism of mechanical responses of granular materials, such as sand and gravel. The parametric calibration of inter-particle contact model for DEM simulations has a significant influence on the simulated results. The nano-indentation tests are employed to measure the Young's modulus of glass beads, and the ultrasonic wave velocity tests on a glass block of the same material are conducted to obtain the Young's modulus of glass. The comparison between the Young's moduli from the two methods indicates that the nano-indentation tests are reliable in measuring the Young's modulus of the materials. Finally, the measured elastic modulus is used in DEM simulations to simulate the small-strain shear behaviours. The simulated results agree well with the test data.