It is the fourth meeting between the two leaders so far this year. Xi held talks with Putin in February before the Sochi Winter Olympic Games, and then in May during the fourth summit of the Conference on Interaction and Confidence Building Measures in Asia in Shanghai.
The two presidents met again in July in Brazil ahead of a summit of the emerging-market bloc of BRICS, which groups Brazil, Russia, India, China and South Africa.
Xi has held talks or met with Putin for nine times since he assumed the office of Chinese presidency in March 2013, which testifies to the high level and distinctiveness of China-Russia relations.
Both Xi and Putin will attend the 14th summit of the SCO slated for Thursday and Friday in the Tajik capital.