Data mining is a practical tool that enables us to investigate the large data set, summarize their relations or correlation, analyze these relations, forecast the results, and create the practical models. In recent years, data mining techniques and algorithms help researchers of different sciences to reach their goals. Since the access to the internet and its penetration in different areas becomes as a criterion for evaluating the development of countries, data mining techniques can be used for studying the expansion of internet in today's life. The aim Iran’s 20-year vision plan is developing communication, information and infrastructure of telecommunication according to world improvement. According to the importance of this subject the survey of internet user was implemented. In this paper, characteristics of internet users were studied. These characteristics can be different with regard to social conditions. Next, the data of internet user survey in Tehran province have been used and some features were considered. Clustering algorithms and association rules were applied to study the features of internet users in Tehran. The results can help experts in expanding the use of internet in different areas.