The issues relating to the study of evidence as an inherent part in the proceedings of international commercial arbitration has not been stipulated in details and its particulars has not been clarified. This category is considerable in that whether the arbitration authority can embark upon proving the issue in hand and to investigate the evidence. In fact, the purpose of this article is to examine and to pay attention in this case and to determine the role of each party to arbitration and arbitration authority regarding the evidence. Considering the regulations and rules governing the international commercial arbitration we understand that taking evidence by the arbitrator is to follow the increase of claim factual aspects and delay of proceedings. To this end, due to special feature of arbitration body and the necessity to regard the impartiality of arbitration is in conflict with the soul of existing regulations. Therefore, the active role in connection with proving the issue is on the arbitration parties and they oblige to prove their allegations according to this rule that the burden of proof is on claimant. This article with reviewing and analyzing in applicable systems to arbitration proceedings introduce the prevailing system regarding the admissibility and presentation of evidence in international commercial arbitration.