In this article, the negotiation style of this country is examined in contemporary history, focusing on the historical context of JCPOA negotiations. This category is evaluated in the framework of "the spirit of negotiations" in the sense that diplomatic negotiations in addition to concrete examples; It also follows a not-so-obvious and hidden format, which may not be visible and touchable, but in the end, it dominates the entire body of negotiations and plays a pivotal role. Therefore, the problem of the research is the analysis of the spirit of the laws or the fundamental rules that govern the negotiations of Iranians in national issues, and the question of the present article is whether there is a rule that governs the sensitive and national negotiations of Iranians in the international environment? What style of negotiations did the Iranians follow and what was the spirit of the rules governing the negotiations? The present research is trying to analyze the spirit of the negotiations leading to the JCPOA and the period after it in the aforementioned framework and examine the causes of its failure and success in different periods of time and based on multiple variables