Motivated by the fact that the most prominent feature in an XML schema is its hierarchical structure, we propose a new structure matching approach for XML schema matching. Our approach is based on the node context, which is reflected by its ancestor and its descendants including both the immediate children and the leaves of subtrees rooted at the element. To this end and to quickly extract context information of the element, we present XML schemas as sequences of labels and numbers by Prüfer's method that constructs a one-to-one correspondence between schema trees and sequences. We benefit from label sequences to determine terminological semantic similarities between two schema concepts. We then develop a novel structural algorithm which is based on number sequences and is used to prune many false positive candidates. Finally, we combine two similarity measures to obtain the total similarity between schema' elements. Our experimental results demonstrate the performance benefits of our proposed approach.