Putin and Xi oversaw the signing of more than 40 co-operation agreements in areas such as trade, technology and media exchanges.
They stressed their growing trade ties, particularly in oil and natural gas, and declared themselves aligned on international relations.
The countries' ties have reached "the highest level in history", Xi said after the signing ceremony on Wednesday, speaking to members of the delegations and journalists.
The two sides also agreed to extend a friendship treaty first signed in 2001.
Putin told those in the room that "the driving force behind economic co-operation is Russian-Chinese collaboration in the energy sector".
"Amid the crisis in the Middle East, Russia continues to maintain its role as a reliable supplier of resources, while China remains a responsible consumer of these resources," Putin said.
Xi stressed the need for a "complete cessation of hostilities" in the Middle East, according to Chinese state media.
"An early end to the conflict will help reduce disruptions to energy supply stability, the smooth flow of industrial and supply chains, and international trade order," Xi said.
China became Russia's top trading partner after Moscow's full-scale invasion of Ukraine in 2022.
Beijing has said it is neutral in the conflict while maintaining trade ties with the Kremlin despite economic and financial sanctions by the US and Europe.
China is also the top customer for Russian oil and gas supplies, and Moscow expects the war in Iran to increase the demand.
There was no visible progress, however, on the prospective Power of Siberia 2 natural gas pipeline that Russia has pushed to boost exports to China.
Bilateral trade between the two countries reached about $US228 billion in 2025, according to Xinhua news agency.
Xi said trade in areas such as energy served as "stabilising pillars" of the relationship and pledged to accelerate co-operation in other areas, such as artificial intelligence, the digital economy and technological innovation.
The trip comes just days after Trump's own visit to Beijing - in a sequence meant to cement Beijing's image as an influential superpower, experts say.
Putin also described China and Russia's co-operation in foreign policy as "one of the key stabilising factors on the international stage".
"In the current tense situation on the international stage, our close co-operation is particularly in demand," he said.
Xi also repeated criticisms of "unilateralism and hegemonism", in what appeared to be a veiled reference to US actions, saying "the world faces the danger of reverting to the law of the jungle".
In February 2022, just weeks before Russia's invasion of Ukraine, China and Russia announced a "no limits" partnership during a trip by Putin to Beijing.
Beijing says it is neutral in the conflict, though in practice it supports Moscow through frequent state visits, growing trade and joint military drills.
Putin invited Xi to visit Russia in 2027 and said he would take part in the Asia-Pacific Economic Co-operation summit in November in China.
Both Putin and Xi continued to praise their close personal ties, with Xi greeting Putin by calling him "my dear friend".
"We are truly delighted to see you. We keep in constant touch, both personally and through our aides in the government."
Xi also addressed Putin as "my longtime friend" at the start of their talks and said it was important to build upon "the foundation of mutual trust" between the countries.
