Mehr al-Mazl is a financial measure that is proved for the woman in cases such as marriage without specifying the dowry (depending on the situation), the relationship caused by doubt. The civil law is silent about the maximum allowed amount in determining this seal. It may be said that due to the fact that the legislator did not mention the limit of mehr al-mathl, the principle is that there is no limit. While the basis of this discussion is in jurisprudence. When referring to the fatwas of the jurists, it can be seen that there is a difference of opinion among the jurists in this field. Some believe in not determining the limit, some believe in detail, and a group like famous jurists and some contemporaries like Imam believe that Mehr al-Mathl should not exceed the amount of Mehr al-Sunnah. Considering that according to Article 167 of the Constitution, in cases of silence of the law, it is necessary to refer to the valid fatwas of jurists, this idea is created that a limit should be set for the mehr al-mathl in law and more than the mehr al-sane should be returned to the couple. This research, using the library method and descriptively and analytically, examines the opinions of determining the limit for Mehr al-Mazl, and finally, the opinion of not determining the limit is accepted and it is suggested to clarify this issue in the text of the law.