The measure of distance between UML diagrams is a crucial step to support the integration of UML sequence diagrams. This distance is used for measuring the difference between two sequences messages exchanged by objects. Even though UML sequence diagram is widely used, nothing has been done to support to find matches for short sequence of messages in many longer interactions between objects. Unfortunately, calculating this distance is still a great challenge for developers given the problem at hand as semantic information is typically not included in any formal way in the models. Therefore, this work focuses on proposing an algorithm for calculating distance between sequence diagrams to enable an identification of similarity between models. For this, the proposed algorithm was implemented and incorporated into a model composition tools, namely MoCoTo. Our preliminary evaluation indicated that algorithm was able to measure the distance between two UML sequence diagrams properly.