Putin arrived earlier on Thursday for a two-day state visit that will include detailed talks on Ukraine, Asia, energy and trade with Xi, his most powerful political backer and fellow geopolitical rival of the United States.
"The China-Russia relationship today is hard-earned, and the two sides need to cherish and nurture it," Xi told Putin as they met at the Great Hall of the People in Beijing for their opening session.
"China is willing to ... jointly achieve the development and rejuvenation of our respective countries, and work together to uphold fairness and justice in the world."
China and Russia declared a "no limits" partnership in February 2022 when Putin visited Beijing just days before he sent tens of thousands of troops into Ukraine, triggering the deadliest land war in Europe since World War II.
By picking China for his first foreign trip since being sworn in for a six-year term that will keep him in power until at least 2030, Putin is sending a message to the world about his priorities and the strength of his personal ties with Xi.
As they met, Putin told Xi that their co-operation was a stabilising factor.
"It is of crucial significance that relations between Russia and China are not opportunistic and are not directed against anyone," Russia's RIA Novosti news agency cited Putin as saying.
In an earlier interview with China's Xinhua news agency before his departure, Putin praised Xi for helping to build a "strategic partnership" with Russia based on national interests and deep mutual trust.
"It was the unprecedentedly high level of the strategic partnership between our countries that determined my choice of China as the first state that I would visit after taking office as president," Putin said.
"We will try to establish closer co-operation in the fields of industry and high technology, space and peaceful nuclear energy, artificial intelligence, renewable energy sources and other innovative sectors."
Informal chats between the leaders and senior officials of both sides to be held over tea and dinner later on Thursday are expected to be key to the two-day trip.
Kremlin foreign policy adviser Yuri Ushakov said those talks would range over Ukraine, Asia, energy and trade.
Putin's newly appointed defence minister, Andrei Belousov, as well as Foreign Minister Sergei Lavrov, Security Council Secretary Sergei Shoigu and Ushakov will also attend, along with Russia's most powerful CEOs.
It was not immediately clear if Gazprom CEO Alexei Miller would go to China as he was on a working visit to Iran on Wednesday.
