In order to investigate the effects of elasticity and plasticity on the stress-strain characteristics of cement sand and gravel (CSG) and to establish the dilatancy equation, a series of triaxial compression tests, isotropic loading and unloading tests, and triaxial loading and unloading tests of CSG materials with different cement contents under different confining pressures were carried out to systematically study the dilatancy characteristics, by means of the research method for the dilatancy characteristics of coarse-grained soil or rockfill. The results show that, both elastic and plastic strains cannot be ignored during the loading of CSG, and the CSG shows the dilatancy under the low confining pressure, while the dilatancy transits to the shrinkage with the increase of confining pressure. The elastomer strain and elastic shear strain of CSG were obtained by test data and dilatancy characteristic curves of CSG materials with and without considering elastic strain were also compared. The study reveals that the elastic strain of CSG has a greater influence on the dilatancy, and only with the high cement content and under the high confining pressure, the influence of elastic strain can be ignored. Finally, the quadratic function can well describe the dilatancy characteristics of CSG.