There has been a heated debate about the position of competition law in the European Union (EU) because of the commission’s largely involvement on Member-states internal affairs and competition policies to ensure the single market. Nowadays, the issue is becoming more popular with the consideration of the populist member-states’ governments and the its effect on EU parliament election. The plural voices on the competition policies from member-states will affect the nature of ensuring the single market. This essay will discuss and show the aspects of federal characteristic in the scope of the EU competition law. The doctrine of supremacy and the direct effect of competition law will be covered by considering the EU Treaties, Regulations and cases. Additionally, institutions and the relationship of institutions is another significant aspect to cover and understand the system of EU competition law. Next, the procedural law of competition law which was believed a part of internal affair for each member-states and the highly broad definitions in the treaties will be the second part of this essay. How much the EU is a union or federation with perspective of competition law practise will be discussed.