In this study, the thin-walled plate with the central open hole made of carbon-epoxy composite was investigated. The plate was tested in tension to investigate the mechanism of crack formation in the composite structure. The studies were carried out using two individual methods: experimental and numerical. In the experiment test, load was measured as the function of plate elongation. The Plate elongation was analysed using the Aramis optical non-contact measurement system. In the numerical study, the FEM model reproducing the experimental conditions was developed in the Abaqus software. The cracking process was modelled using the XFEM method (extended finite element method). This procedure allowed the of the composite to be examined over the full range of the tensile load. The behaviour of the plate with a circular open hole was investigated before damage symptoms and the damage initiation load was determined. The study continued to analyse the initial cracking and delamination of the laminate layers, together with crack propagation leading to cracking of all the laminate layers (complete failure of the composite structure). The novelty of this study is that it uses the popular XFEM method to describe the cracking and failure of the composite structure. In addition, the study proposes the novel method for determining the crack initiation and failure loads of the composite plate under tension, and the results obtained thereby are verified numerically.