In this study, the EU application of intervening policy of government, whose importance is recognized once more, together with economic crisis, is examined and in the study carried out, First, the concept "fiscal discipline" and its importance are considered. How fiscal discipline should be provided, unless it is, the effects of resulting problem of fiscal indiscipline are discussed. Following these, the issue of fiscal rules, which are in the key position in providing the fiscal discipline, is described. The second section of study consists of the issues of Maastricht Agreement and Stability and Growth Pact, applications of European Union Fiscal Rules. Together with implementation of these rules, what change in European Union, the importance of these rules for European Union, and how much is achieved to the target set are examined. The third section of study consists of the issue of European Union Tax Policies.The fourth section of study consists of the issue of European Union Economic Crisis.