The diversity of modern international contracts models, which are accompanied by the emergence of traditional approaches of conflict that fail at finding appropriate solutions for these advanced contracts. In view of what leads to the application of one of the national laws that were originally enacted to govern internal relations, which in turn has led to the lack of response to the nature of these contracts that require multiple attribution links , making it difficult to claim a single legal and sufficient system for its rule. This has called on the private international law jurists to stress the need for some rules with direct application to find solutions to the problem of conflict within the framework of private international relations. When considering the adoption of the substantive rules approach, the issue under investigation must be taken into consideration in terms of the way in which the topic is pondered via investigating the cases that are within the jurisdiction of the national judiciary or cases that fall outside the realm of this jurisdiction. As far as the first case is concerned, the substantive rules are applied for the settlement of disputes is within the provisions of the national law. As for the second case, the arbitrator shall apply the substantive rules to find solutions to the issues of conflict resolution. The current study has touched upon the first requirement to the implementation of the provisions of the rules of national substantive ones, while in the second requirement, the present paper has concentrated on the implementation of the provisions of the rules of foreign substantive rules, and finally the most important results and recommendations that are mentioned in the work are discussed .