Iran and Saudi Arabia are two big rival in the Middle East. Saudi Arabia was against the JCPOA and try to destroy Iran deal after Donald trump victory in American president election. Riyadh had promised to increase its oil production after the US imposed an oil embargo on Iran and involved in American maximum pressure against Iran. While Saudi Arabia considered itself a strategic partner of the United States, the attack on Aramco's oil facilities changed the balance in the region entirely. The main question in this article is based on why Saudi Arabia suddenly changed its foreign policy towards Iran after the attack on Aramco oil facilities. The findings show the fact that after the withdrawal of the United States from the JCPOA, Riyadh thought that Washington would use all its options, including the military option, to intimidate Iran in confrontation with Tehran and eventually force Tehran to negotiate and give more concessions. With time passage, America not only did not take advantage of the military option against Iran, but Washington officials have repeatedly announced that they do not think about the military option in confronting Iran. The attack on Aramco's oil facilities changed the balance of power in the region and showed that contrary to what Saudi Arabia thought, America is not willing to engage in a military confrontation with Iran, or at least it was not willing to go to war with Tehran because of Riyadh. This forced Riyadh's authority to rethink its foreign policy towards Tehran. Choosing the policy of negotiation and dialogue as well as accepting the mediation of Pakistan and Oman was the policy that Riyadh took towards Tehran. The method of this research is descriptive-analytical and the game theory approach has been used to analyze the research topic.