The event, known as Vostok 2018, was condemned by Nato as preparation for a “large-scale conflict”.
The Russian defence ministry yesterday released footage of planes, helicopters, ships and military vehicles involved in the huge exercise.
It is thought to be the largest Russian military drill since the Cold War era.
Russian President Vladimir Putin and Chinese counterpart Xi Jinping were involved in talks at an economic forum in Vladivostok in Russia’s far east yesterday.
The two leaders have pledged to work together to tackle international problems, and were even pictured together tucking into pancakes, caviar and vodka at a function.
Putin admitted Russia had forged close ties with China and said: “We have trustworthy ties in political, security and defence spheres.
Xi, who has been at loggerheads with the US over trade, said he believed building strong relationships with Russia was vital.
He added he believed the “friendship is getting stronger all the time” between the two countries.
Tensions have been heightened between Russia and the West in the wake of ongoing conflicts in Ukraine and Syria and the Novichok attack in Salisbury.
Russian Defence Minister Sergei Shoigu said the war games were one of the biggest ever staged, with 300,000 soldiers, 36,000 military vehicles, 1,000 planes and 80 warships involved.
Shoigu said the exercises would be on an “unprecedented scale both in territory and number of troops involved”.
He added: “Imagine 36,000 military vehicles moving at the same time – tanks, armoured personnel carriers, infantry fighting vehicles, and all of this, of course, in conditions as close to a combat situation as possible.”
Some 30 aircraft from the Chinese air force will be involved in the fiveday drills.
The Chinese claimed the operation was not “directed against any third party” but said it was aimed at focusing on “defences, firepower strikes and counterattack”.
Vostok 2018 is home to more than twice the number of troops in the whole of the British Armed Forces, whose numbers stand under 150,000.
Russia’s latest hardware is being showcased during the war games, including its Iskander missiles that can carry nuclear warheads, the T-80 and T-90 tanks and its new Su-34 and Su-35 fighter planes.
The Russian naval fleet also sent several frigates equipped with Kalibr missiles that have been used in Syria.
Anti-aircraft technology will be at the heart of the drills today, but the main exercises will be held tomorrow, according to the country’s defence ministry.
Nato spokesman Dylan White previously warned Russia was building up its military strength.
He said: “It fits into a pattern we have seen over time – a more assertive Russia, increasing its defence budget and military presence.”
Kremlin spokesman Dmitry Peskov last month said Russia’s “ability to defend itself in the current international situation is justified, essential and without alternative”.