The victory snapped Japan’s dominance in the tournament dating back to Bangkok in 2013 and ended the Tokyo Olympic silver medallist’s dream of making it six in a row.
No nation other than Japan, China or South Africa has won the Asia Cup since its inception in 1965.
Hosts Australia took bronze for the third consecutive tournament after crushing New Zealand 81-59.
Weina Jin scored an early bucket for China but Japan quickly found their stride in an intense first quarter that ended level-pegging at 17-17.
With tournament MVP Han, who towers 6 feet 10 inches (2.08 metres), leading the way, China went on a 7-0 run in the second stanza to pull clear, but again a relentless Japan came roaring back.
With lightning-fast transition and aggressive defence, Japan went 18-2 to reach half-time 35-26 in front.
China lifted the tempo in the third stanza and edged a point clear, but Japan weathered the storm to take a 51-48 lead into the home stretch.
But in a nail-biting finish, the Chinese held their nerve to triumph in a game that went to the wire.
All four semi-finalists in the eight-team competition secured a place at the 2024 Paris Olympic qualifying tournament.