The plane is the heaviest in the world. It has maximum weight of 700 tons, 200 tons more than a 747, and 50 tons more than the Airbus AN380–800F
The plane packs 32 wheels (the A380 has 22) and can fly at a cruising speed of nearly 500 miles per hour with a maximum range of around 9,500 miles — without subtracting for tonnage added inside Mriya’s enormous hold.
The An-225 needs a minimum of 11,500 feet while carrying its maximum payload to takeoff.
China's runway at the Fiery Cross Reef [South China Sea] is 3,000 meters (10,000 feet) long and is one of three China has been building for more than a year by dredging sand up onto reefs and atolls in the Spratly archipelago. So it is not long enough for maximum An-225 payload unless it is lengthened another 1500 to 2000 feet.
China does have at least seven 4000+ meter runways
SOURCES - Antonov, war is boring, reuters, wikipedia