Studies on the Arabic language started with the expansion of the Islamic world with conquests and the widespread incidents of lahn that emerged as a result of the conversion of people from different nations. The language mistakes made by those who learned Arabic afterwards while speaking Arabic and reading the Quran revealed the necessity of determining and capturing the rules of this language. In this context, it is accepted that the first studies to determine the rules of the Arabic language were carried out by Abu al-Aswad al-Duali (d. 69/688) during the caliphate of Hadrat Ali. In the second century AH, the works of grammar have expanded and systematized, grammatical discussions have emerged, schools have appeared and voluminous works have begun to be written. Later, the necessity to handle the grammar literature which volumes were written about its, with a methodological and systematic approach has arisen. These studies, named as usul al-nahiv, were carried out with inspiration from fiqh method and logic. Later, the works of usul- al-nahiv have accepted as a science separate from the science of grammar and independent works have written on this subject. In this context, it is accepted that the first independent work written in the field of usul al-nahiv is the ‘luma‘u'l-edille’ of Kamal al-Din al-Anbari. The work named ‘al-Iktirah fî usuli'n-nahv’ by Jamal al-Din as-Suyuti, who lived approximately four centuries after Anbari, is another source that gained fame in this field. In the introduction of his work, Suyûtî has stated that the first independent work on the usul al-nahiv belongs to himself. However, he has not neglected to quote from the work of Enbari, who lived about four centuries ago before him. In this study, we compared these two main sources of usul al-nahiv in terms of content and method. Based on the findings we have obtained in the study, we can say that Enbari has tried to determine the rules about the sources of the usul al-nahiv and the approach to these sources. We can say that Suyuti has written his work mostly as a compilation. Because Suyuti often has quoted works written before him in the work. Both authors first have made definitions of many concepts such as grammar, usul al-nahiv method and evidence, and then have explained the subtleties of these definitions. Both authors have dealt with the issue of the sources of nahvin. While Enbari has listed them as transfer, comparison and istishabu'l-hal, Suyûtî used the term sema instead of transfer and added the ‘ijma’ to these sources. Anbari has mentioned only the Arabic word that reached the level of reputation in addition to the Qur'an, and has not mentioned the hadiths of the Prophet. Suyuti, on the other hand, has accepted the Quran along with all its readings as sound evidence and has set certain criteria about hadiths. Both authors have described and divided the syllogism in detail. However, the division made by both is different from each other. Enbari has made the definition of cause, which is one of the main issues of grammar debates, and discussed it in detail. Suyûtî, on the other hand, has not entered the definition of cause, but he has examined the subject in detail by making quotations from other works. Regarding the method, it can be said that both authors have adopted the method of fiqh method researchers and logicians in general, unlike the classical nahivist method. As a matter of fact, the elaboration of the grammar sources first, the order and method of deducing from them shows that the method of the field researchers mentioned above has been adopted. In this context, the methodology that Enbari put forward in his work is a first in his field. Although the subjects of usul al-nahiv were dealt with scattered in different works before him, the privilege of systematizing them belongs to him. Suyuti's work, on the other hand, gives a more systematic and orderly image than Enbari's.