Putin, re-elected to his fourth Kremlin term in March, arrived at the grandiose Great Hall of the People in Beijing for talks with Xi, who could stay in power for life after term limits were lifted this year.
The two heads of state reviewed a military honour guard and greeted flag-waving children during the welcoming ceremony before retreating into the vast building.
The most powerful Russian and Chinese leaders in decades, Xi and Putin have built closer ties while US President Donald Trump has labelled both countries as economic rivals that challenge US interests and values.
"Both share scepticism towards American hegemony and distrust US intentions, both are authoritarian personalistic rulers," he said.
Putin played up his bond with his "good friend" Xi in an interview with China's state broadcaster CGTN this week.
Xi "is approachable and sincere", Putin told CGTN. "But he's also a very dependable man to work with." Maria Repnikova, director of the Center for Global Information Studies at Georgia State University in the US, said China makes
Russia look "stronger and more relevant" on the global stage.
"Trump's policies justified (the) growing closeness, especially for Russia but also for China given the volatile relationship with the United States," Repnikova told AFP.
But, she said "it's an asymmetrical relationship with Russia more dependent on China than vice versa, especially in the economic sphere".
Putin told CGTN that the SCO had "small" objectives when it was founded two decades ago but that it was now evolving into a larger global force.
Iranian President Hassan Rouhani, whose country is an observer member of the SCO, will also attend the summit at a time when China and Russia are seeking to save the Iran nuclear deal following Trump's withdrawal from the pact.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)