In recent years, freedom in design of composite microstructure has been improved because of the development of the manufacturing technology of various cross-sectional carbon fibers. Therefore, numerous candidates of composite microstructure must be considered for microscopic optimization of composite. To this end, this study develops mesh-free microscale simulation tool consisting of two kinds of computational techniques; homogenization method and extended finite element method (XFEM). For the evaluation of an effect of microstructure on the macroscopic mechanical and fracture properties, homogenization method was introduced. Additionally, the composite microstructure (i.e., fiber / matrix interface) is able to be modeled independently of the mesh by the XFEM. The proposed tool makes it possible to conduct comprehensive numerical investigation into various composite microstructures without remeshing.