The research aims to show the refutations of the reasons that Imam Assalimi has rooted in his book Tala't Ashams and to compare his rooting of the rules (Alqawaid) with his jurisprudential applications on them. That is to demonstrate the extent to which his rooting of these rules in the Tala't Ashams corresponds to its applications in the Book of Purity from his book Ma'arij Alaamaal. The research consists of two chapters. The first chapter looks at Imam Assalimi's rooting of these refutations of reasons, and the second discussses his applications of refutations of reasons. The results of this study have shown that Imam Assalimi has defined the concept of reason (Illah) as the one that identifies the ruling or as "rule identifier". Moreover, the effect of selecting this definition by Imam Assalimi was clearly seen in a number of issues pertaining to reasons (Illah) such as the permissibility of reasoning using the limited reason (Illah Qasirah), permissibility of reasoning the legal ruling using another legal ruling, permissibility to delay the reason (Illah) after the original ruling, and the permissibility of absolute reasoning using the non-existent reason. Imam Assalimi has listed 25 refutations although he mentioned other two meanings for the breaking refutation, which makes them 26. He also mentioned that the objections are not limited to the refutations he mentioned but he approved 25 and rejected one which is described as the breaking one. That one is the one that shows the wisdom behind some issues but does not have a reason or a ruling. The applications of the refutations of reasons that Imam Assalimi used in his book in Ma'arij Alaamal were compatible with what he had rooted in Tala't Ashams. However, his rooting of those rules were in compatible with his applications when it comes to the issue of the using deductive analogy (qias) of ablution of the Prayer (wudhu) with ablution using soil (tayamum). He refused it here because it is using deductive analogy (qiyas) of the original ablution instead of the alternative (tayammum) although he has allowed it when he mentioned the conditions of reason (Illah). There are other jurisprudential applications that appeared in Ma'arij Alaamal that Imam Assalimi has not mentioned among the ones he mentioned in Tala't Ashams and they are of three types: The first type is not approving some types of deductive analogy (qiyas) such as reasoning using the names, affirming the cause by deductive analogy (qiyas), and deductive analogy (qiyas) in acts of worships (Ibadat). The second type refers to the absence of one of the conditions, such as the absence of the condition that the original should not be used before the branch, which is not a condition taken by Imam Assalimi, and the absence of a condition of equal judgment between the original and the branch of ruling. The third type: the division that Assalimi had ignored. It is mentioned by a number of scholars of fundamental of Jurisprudence