Chen Shengqi, head of the drill's team of appraising experts, was quoted as saying that the warships had handled air, underwater and surface threats that closely resembled real combat.
The People's Liberation Army marked its 89th anniversary on Monday, which was also Army Day.
The exercises were the latest in a series of drills conducted amid rising maritime tensions. In July, the Navy held two South China Sea drills.
A number of additional exercises are planned as the country picks up the pace of its military reform, characterized by a historic shift in the PLA's organization and structure to gain a more efficient command system.