In order to facilitate query processing for XML data, several path indexing, labelling and numbering scheme have been proposed. However, if XML data need to be updated frequently, most of these approaches will need to re-compute existing labels which is rather time consuming. In this paper, we propose a new Labelling Scheme for Dynamic XML data (LSDX) that supports the representation of the ancestor – descendant relationship and sibling relationship between nodes. Moreover, LSDX supports the process of updating XML data without the need of re-labelling existing labels, hence facilitating fast update. Some experimental works have been conducted to show its effectiveness.