As one of the Alternative Dispute Resolutions, arbitration has become popular for a long time which has a long history since the Ancient Roman Commercial Trade Development Period. Until today, arbitration is still so welcomed since it has some advantages that litigation does not have, for example, privacy and efficiency. Confidentiality is usually cited as one of the advantages of arbitration over litigation so that dispute parties are more likely to choose arbitration to settle their disputes. However, confidentiality of arbitration has just gained attention from the field of international commercial arbitration in recent years. Due to the special nature of arbitration, the arbitration proceedings are regulated by the different arbitration rules of the specific institutes and the national law of the country where the institute is located. However, the problem is that different national laws and arbitration rules have different achievements on this issue. Some countries even do not recognize that there is an implied duty of confidentiality between the dispute parties. In 2010 International Law Association Conference held in Hague, confidentiality has been proposed as an important issue. The development of confidentiality has attracted the attention of the scholars in the field of arbitration. This thesis aims to give a comparative study about confidentiality on the levels of national laws and arbitration rules and find the issues regarding the development of confidentiality. With a good understanding of confidentiality, at the end, I will give some suggestions for protection and development of confidentiality in the future.