Abstract: The deficiency of orientation and weight calculation methods for a microplane model is pointed out after its discretization algorithm analysis.A new microplane grid division method is proposed to solve the problem of non-uniform orientations and the vague microplane physical concept in an original method.Firstly,the unit regular polyhedron surface is divided into regular grids,and then mapping them to the unit sphere surface to generate a series of spherical triangles,of which each one represents a microplane.The method of calculating microplane weights is derived from spherical geometry theory.The optimization goal of fitting macro elastic stiffness matrix is proposed in the program evaluation.Calculation results shows that the method proposed can accurately obtain programs of uniform microplane shape and size.