War is the most horrifying activity in human history. Not only male soldiers sacrificed in the battleground but also females became the tragic victims during armed conflicts. Because of their gender, women are more vulnerable to serious sexual violation than men. During armed conflicts, sexual violence has almost become a collateral behavior, even a weapon of the war. The development of punishment against sexual violence and women’s sexual rights protection during armed conflict has a long history. The earliest attempts are found in punishments happened before the Second World War. However, since women’s rights have long been ignored, sexual violence crimes causes of weak punishment in international criminal law. Until the establishment of International Criminal Court in 2002, sexual violence crimes were finally legislated in crimes against humanity in the Rome Statute. Nevertheless, forced marriage as a new form of crimes against humanity is lack of explicit recognition as an independent category of crimes against humanity. Through elaborating on Jus cogens, customary international law, the international treaties related to the criminalization of forced marriage and the comparison on the validity of marriage in domestic law between different countries, the thesis mainly provides reasons why forced marriage is a new form of crimes against humanity of the Rome Statute. Furthermore, by analyzing forced marriage in the practice of the Special Court of Serra Leone and the period of Khmer Rouge in Cambodia, the thesis is going to signify the importance of explicit recognition of forced marriage as an independent category of crimes against humanity. The thesis aims to attach importance to women’s sexual rights protection during armed conflicts by the government and people of all circles. With analysis of the practices by different international courts, it is important to criminalize forced marriage as an independent category of crimes against humanity.