Democracy is an important value for the European Union(EU). However the EU has suffered for the lack of democracy, whilst most of countries are trust in respect of democracy in the EU. The EU is a new subject for theories of legitimacy which poses fundamental questions to the established principles and concepts of democratic theory. With its current form,the model of democracy in the EU does not conform to liberal parliamentary democracy or federal state, consensus, deliberative or corporatist models. The EU cannot be democratically legitimized by the model of a nation-state. The argument regarding the democratic deficit of the EU institutions reveals integrated and deeply seated political problems. There is a multitude of reasons and solutions regarding the democratic deficit in the EU, which lead to complex interpretations. This study proceeds on a road map that sheds light on primary and secondary law that are relevant to an understanding of the problem of democratic deficit.