Abstract: A numerical model BPM3D(Beam-Particle Model in Three Dimensions) was developed to simulate the mechanical properties and fracture process of rock under uniaxial tension.This numerical method simulating damage and fragmentation phenomena of rock-like material was presented on the basis of discrete element method(DEM) and lattice model of finite element method(FEM).Material was schematized at mesoscale level as a three dimensional assembly of particle elements in the BPM3D and the nearest neighboring particles were connected through a lattice of elastic beam elements of FEM.The mechanical properties of beams in BPM3D were randomly allocated according to Weibull distribution to reflect the spatial variation of mechanical parameters in rock.Cracks in material were simulated through breaking beam elements.Compact and anisotropic synthetic media were generated automatically and were used to investigate the mechanical behavior of rock.The numerical simulation results of rock fracture process under uniaxial tension showed that the initiation,propagation and linking each other in the rock samples at mesoscale level produced the macro-failure of rock samples.The comparison of the numerical simulation result with the experimental result proved how highly appropriate this method was.The fracture mechanics of anisotropic brittle rock was discussed based on the numerical simulation results.