Introduction. The article is devoted to the problem of establishing the eastern border of the Saka culture of Alai. An important role in understanding of this problem is played by the Touyun burial ground, located in the southwestern part of Xinjiang, close to Kyrgyzstan. Materials and methods. This burial ground has specific funeral rites, which demonstrate the characteristic features peculiar to the Saka culture of Alai. In particular, these are burials in stone boxes, crypt-like stone structures and at the level of the ancient surface, constructed under low stone-earth burial mounds. Burials in them were both single and multi-act. The buried people in these burials were in an elongated position with orientation of the sculls to the west and northwest direction. The funeral inventory from Touyun was relatively poor and represented by a couple of ceramic vessels, jewelry items (earring, bracelet, and beads), a belt garment (belt buckle), household items (sumac, awls) and clothing items (plaques). Results and discussion. These funeral objects, based on analogies, allowed us to establish the time of existence of the Touyun burial ground, which fits into the chronological framework of the end of the 5th - 3rd centuries BC. It is evident, that this necropolis appears as a result of the migration of the Saka population from the eastern part of the Alai Valley. The occupying this territory group of Alai Saka was appeared in the contact zone with the population of the Saka culture of Tien Shan region, with which, apparently, they established marital ties. Currently, the Touyun burial ground is the easternmost site of the Saka culture of Alai, which makes it possible to expand the border of this culture by more than 130 km to the east than previously thought. It also made it possible to significantly clarify the real areas of the main archaeological cultures in the southwestern part of Xinjiang such as the Saka cultures of Alai, Pamir and Tien Shan region.