Abstract: This article is concerned with the multi-scale numerical simulation of structures through the ARLEQUIN method and the extended finite element method (XFEM). The basic concepts of the extended finite element method and the ARLEQUIN method are introduced. Based on the combination of the ARLEQUIN method and the extended finite element method, the Matlab code for the multi-scale simulation of structures has been developed. The stress analysis of a plate with a prescribed edge crack is done and the stress intensity factor around crack tip is calculated. In addition, the stress concentration analysis of a square plate with a circular hole at the center is presented. The numerical results show the correctness of the program as well as the feasibility of the multi-scale numerical simulation with the combination of the Arlequin method and the extended finite element method.