Text document classification is an important research topic in the field of information retrieval, and so it is how we represent the information extracted from the documents to be classified. There exists document classification methods and techniques based on the vector space model, which doesn't capture the relation between words, which is considered of importance to make a better comparison and therefore classification. For this reason, two significant contributions were made, the first one is the way to create the feature vector for document comparison, which uses adapted concepts of non-rigid 3D models comparison and graphs as a data structure to represent such documents. The second contribution is the classification method itself, which uses the representative feature vectors of each category to classify new documents.