By using the lattice model combined with finite element methods and statistical techniques,anumerical approach is developed to establish mechanical models of three-dimensional heterogeneous brittlematerials.A special numerical code is introduced,in which a lattice model and statistical approaches areused to simulate the initial heterogeneity of material properties.The size of displacement-load step is adap-tively determined so that only few elements would fail in each load step.When the tensile principal strain inan element exceeds the ultimate strain of this element,the element is considered broken and its Young’smodulus is set to be very low.Some important behaviors of heterogeneous brittle materials are indicated usingthis code.Load-displacement curves and figures of three-dimensional fracture patterns are also numericallyobtained,which are similar to those observed in laboratory tests. By using the lattice model combined with finite element methods and statistical techniques, anumerical approach is developed to establish mechanical models of three-dimensional heterogeneous brittlematerials. A special numerical code is introduced, in which a lattice model and statistical approaches areused to simulate the initial heterogeneity of material properties. The size of displacement-load step is adap-tively determined so that only only elements would fail in each load step. Where the tensile principal strain in element exceeds the ultimate strain of this element, the element is broken and its meaning Young important patterns of heterogeneous brittle materials are indicated using laboratory code.