The article contains an analysis of the problem of interrelation between the nomadic and settled peoples of Middle Asia at the time of Mongolian invasion. Special attention has been given to the influence of the relations between these peoples on the formation of the Khorezmshah-Anushteginids' state and also on the further history of this state and on its conquest by the Mongols. The author also pays attention to the formation of the image of a "nomad" in the Arabic and Persian sources of the epoch of the Mongolian conquest: the study of the evolution of this image allows to see the attitude of settled peoples to nomads depending on time and the political situation. In the author's opinion it was important to disclose how quickly some nomadic peoples became part of the Moslem society and what were the conditions of this process. On the basis of the information of the sources he emphasizes the fact that the Mongol conquerors became part of the Middle Asian society quickly enough whereas the nomadic Turks mostle continued to remain "alien" for the settled population of this region.