One of the important consequences of the emergence of the Seljuk government was the changes that took place in the land ownership system. These changes were mostly related to military Eqtā, that is, parts of the land that were given to the corps instead of their dues. In fact, the Eqtā system that reached its final stage in the Seljuk period brought about fundamental changes in the concept of "Melk" and land ownership in Islamic Iran. In this research, an attempt is made to examine and analyze these transformations and answer the main question, what were the most important effects of the Eqtā system on the landholding system of Iran during the Seljuk period? Based on the findings of the research, Eqtā system had harmful effects on the landholding system and land ownership. The immediate and direct effect of establishing the Eqtā system was the sharp reduction of private lands. In fact, large and prosperous lands were taken out of the hands of the owners and became the temporary or permanent possession of the corps. These troops, who had no experience in farming and agriculture, and had no motivation and permanent interest in the land, were only trying to get the most benefit from the land they temporarily occupied in the shortest possible time. The result of this was nothing but anarchy and destruction of prosperous lands.