A deformable spheropolygon-based discrete element method (DSEM) which combines the spheropolygon-based discrete element method (DEM) and the finite element method (FEM) is proposed. In this method

with the rounded discrete elements

the shape of the irregular blocks can be well characterized while the high efficiency advantage of particle discrete element method is also kept. The proposed method can not only eliminate the normal singularity at the corner but also improve the stability and simplify the contact judgment during contact force calculation. Meanwhile

the calculation model of the tangential contact force is also modified to improve the efficiency of contact force calculation. The DSEM breaks through the limitation of the rigid body hypothesis of the spheropolygon. Thus

the interaction between discrete elements with arbitrary shape can be accurately calculated

and the movement and deformation of the elements can also be simulated. Finally

three numerical examples including the dynamic response of statically indeterminate beam

the uniaxial compression test of irregular block

and hopper flow test is simulated using the DSEM to prove that the proposed method can effectively capture both the spatial motion as well as characteristics of elements (such as collision

separation and deformation) and their microscopic mechanical characterization.