Motive is one of the pillars of the spiritual element, which usually has no effect on the realization of the criminal act, criminal liability and punishment; nevertheless, in the past years, the attention of the criminal legislator has been directed to this element more than before and its influence on the spiritual element has increased. Security crimes are one of the most important crimes in which the role of motivation in their realization or the amount of punishment is undeniable. In a descriptive-analytical way, this research has identified the most important methods of proving motive in Iran's legal system and judicial procedure, with an emphasis on security crimes. The findings of the research show that at the legislative level, mechanisms such as filing a character file and paying attention to the time of the crime are among the most important methods to prove the motive in security crimes. At the judicial level, methods such as delegating authority to special officials and referring the matter to an expert are among the most important methods faced by judges in this field; although each of the above methods, depending on the case, has the possibility of violating the defendant's defense rights and disrupting the proceedings within a reasonable time.