They will also visit Moscow's main zoo, where two pandas gifted earlier this year by China are expected to be unveiled.
Russia's annexation of Ukraine's Crimea region in March 2014 led to a serious rift between Moscow and the West and its subsequent turn toward its eastern neighbor.
China and Russian Federation have aligned their foreign policies and other positions at the United Nations on major issues such as Venezuela's economic and political crisis, the Syrian civil war and Iran's nuclear program, usually in direct opposition to the stance taken by Washington.
Ahead of their closed-door meeting in the Russian capital Wednesday, Putin said relations between the erstwhile Cold War foes had "without any exaggeration, reached an unprecedented level". Their last meeting took place at the end of April, when Putin attended the Belt and Road Forum for International Cooperation in Beijing. Bilateral trade increased a year ago by about a quarter to a record $108 billion.
Recognizing that the current worldwide security is facing serious challenges, China and Russian Federation intend to deepen strategic mutual trust and strengthen strategic coordination to firmly safeguard global and regional strategic stability, according to the joint statement.
"Despite all the difficulties, China became a significant creditor and rather significant investor" in Russian Federation at a time when many other investors preferred to pack their bags.
About 1,000 Chinese officials and business executives will attend the St Petersburg International Economic Forum, the biggest foreign delegation.
"For Russia, China is a big lifeline, but for China, Russia is not as important as the strategic relationship with the U.S. or Japan", he said.More news: Amazon Previews Drone Delivery Amid Prime 1-Day Delivery Rollout
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Nevertheless, China's share in Russian foreign trade has almost doubled since then, he added.
Mr Xi and Mr Putin will also watch a performance at Moscow's famed Bolshoi Theatre.
"Looking into the future, a number of factors will support the steady, healthy and sustainable growth of China's economy, including abundant human resources, strong internal driving forces, growing development dynamism and mobilization capability, " Xi said.
Politically, the two countries seem consistently aligned and often vote in unison as permanent members of the UN Security Council.
Before the event, the two heads of state toured a photo exhibition marking the 70th anniversary of the establishment of their countries' diplomatic relations.
The trip to Moscow highlights Beijing's efforts to drum up support both at home and overseas as the President Donald Trump's administration pushes China to do more to redress a huge perennial trade surplus and end policies that US and other foreign companies and governments say violate Beijing's market-opening commitments.
After Washington criticised its rights record, Beijing issued a travel warning to Chinese nationals Tuesday about crime and police harassment in the United States.