The microstructures and local characteristics of ordinary refractory ceramics are heterogeneous. The discrete element (DE) method was used to consider the variation in particle spatial distributions and statistically distributed interface properties (uniform, Weibull) between elements. In addition, three Weibull distributions with different shape parameters were evaluated. A uniaxial tensile test was used to study the effects of particle spatial distributions and interface property distributions on the stress–strain curve, tensile strength, and crack propagation. The results of the test show that the particle spatial distribution significantly influences crack propagation and fracture patterns, and the interface condition plays an important role in mechanical responses, crack propagation, and fracture mechanisms and patterns. The discrete element modelling of uniaxial tensile and compressive tests shows that brittle materials exhibit asymmetric mechanical responses to compression and tension loading including static Young’s modulus.