In recent decades, organizations have increasingly focused on developing ICTs and introducing new e-services to their customers, so they have largely invested in web development and promotional activities.Therefore, it is essential for them to evaluate their websites and identify how well they are structured.and how web pages are organized. Evaluating web structure requires proper methods and measures.This paper intends to model a website as a graph and introduce new measures to evaluate website link structure.The model is based on the analysis of online behavior of the website's visitors. Thus, a real problem of the website of an Iranian university was described and, its structure was evaluated using this model between September-05 to November 2005.