Child marriage is one of the important issues related to children's rights, which is the subject of serious debate and disagreement. In the present paper, an attempt has been made to examine this important issue, what is the approach of jurisprudence regarding child marriage and what are the mechanisms of its prevention from the perspective of criminal law? This paper is descriptive and analytical and the mentioned question has been investigated using the library method. The results of the paper indicate that in jurisprudence, the marriage of children is accepted with the permission of the guardian and considering the best interest of the child and the absence of corruption. Although the legal age of marriage is 13 years for girls and 15 years for boys, in Iran's legal system, it is also possible to marry girls with the guardian permission. The most important mechanism to prevent child marriage is social prevention, including education and cultural promotion and awareness of parents, which is completely possible considering the condition of expediency and non-corruption. The growth of parents' awareness can create mental conditions in them that they have a more up-to-date and broader approach to the concept of children's expediency and are not willing to accept their children's marriage due to different social and cultural conditions. Because paying attention to the fact that reaching the physical and biological threshold (puberty and the start of menstruation) does not mean that a person is suitable for marriage and that children do not have the ability to analyze and evaluate a marriage and it leads to many negative consequences. In addition, it can influence the parents' view about child marriage.