The interaction and balance between fair trial and security-oriented crimes is one of the important topics of discussion and disagreement. A fair trial is the trial of a person in the light of the law and with respect for the rights of citizens and is a basis for promoting the rule of law. Meanwhile, security is one of the most important categories of any political system and its preservation is one of the priorities of the legislator. The purpose of this article is fair trial in security-oriented crimes in Iranian criminal law. This article is theoretical and has been investigated using the analytical descriptive method. The findings indicate that in Iran's criminal law, many examples of fair trial have been accepted, but in crimes against security, in some cases, such as the principle of public proceedings and the lawyer's access to the contents of the case, the fair trial has faced limitations. In fact, in crimes against security, the investigator can block the access of the lawyer to the contents of the case and also in crimes disturbing public order and security, the hearing can be held in private with the opinion of the judge of the case. It is necessary to mention that public order is a general term and it is necessary to specify the concept intended by the legislator, because many crimes may be considered disruptive to public order by the judge and therefore held in private.