Varamin Plain, located on the Jajroud alluvium, has provided suitable conditions for the establishment of human settlements. The result of sedimentation of this alluvium, which is suitable for cultivation, along with hot and dry weather and favorable environmental conditions, has provided the ability to settle and feed human populations in this plain from the Paleolithic period to the present day. At the end of the 6th millennium and up to the middle of the 5th millennium BC, the culture known as Chashmeh Ali was common in large areas of Iran and even outside the current borders of Iran, which, despite the general similarity, had specific characteristics of each region in details. One of these areas is Varamin plain. The creation or destruction of settlements is under the direct influence of environmental factors, and without knowing these factors it is difficult to identify the social, economic and even spiritual dimensions of ancient humans. In fact, the basis of archaeologists' studies is to search and find the interactions between human societies and the surrounding environment, as well as the technologies that human groups have invented to adapt to the environment. The purpose of this research is to investigate the environmental factors in the formation of Cheshmeh Ali culture settlements in Varamin Plain. Therefore, the most important question is what is the relationship between climatic and environmental structures and the formation of Cheshmeh Ali culture's settlements in Varamin Plain? The present research is descriptive and analytical in terms of method. The method of data collection in this research is the type of objective observation, description, and comparative study which has been analyzed and concluded using both field and library methods, along with the use of geographical software and remote sensing.