A condition option is a type of right to terminate a contract necessary for a certain period of time, which arises based on the consent and agreement of the will of the parties to the transaction in the form of a condition included in the contract, which is necessary for one of the parties or both or a third party. The extent of the option of the condition in the necessary contracts is one of the challenges that can be raised, which in Islamic jurisprudence includes criteria such as the combination between the possibility of abatement in the contract and the option of the condition, or the basis of the contract on the contract or the criterion of the duration of the contract. This diversity and difference among the rules and the lack of comprehensive rules to distinguish the mechanisms of the flow of conditions in contracts have been reflected in the legal texts of Iran and other Islamic countries, which makes it necessary to study this issue and reach a proper attitude. The results of the present article, which was carried out with a descriptive-analytical method, state that the condition option is a product of the agreement of the parties to the transaction, and the freedom of will is not absolute and is limited to the way that it does not contradict the book and the Sunnah and causes the analysis of haram or sanctions. Do not become halal. Also, it should not be against good morals and public order. Therefore, by focusing on the principle of sovereignty of the will, non-opposition to Sharia and the law, and considering the role of the nature and necessity of that contract, comprehensive and systematic rules can be presented for the flow of the condition option in contracts.