This article discusses about argument of maslahah mursalah as a source of law. The focus of the study in this paper is a controversial idea between Imam Malik and Imam Shafi'i about maslahah mursalah as a source of law. Controversy thinking between both of them as a source of law. First, Imam Malik used maslahah mursalah as a source of law, but Imam Malik stressed the establishment of the law by taking the benefit and using the ratio, it must not controvert with the rule of law that has been set by nash or ijma '. If there is a controversy then it must precede nash than maslahat. Secondly, Imam Shafi'i did not use maslahah mursalah as a source of law because it did not have a definite standard of nash and qiyas, while Imam Shafi'i’s establ...