It has now appreciated a further 0.3 percent since the July policy move. The yuan, also known as the renminbi, finished at a post-revaluation closing high of 8.0840 to the dollar last Friday, taking its cue from the US currency's strength on international markets.
"Since the yuan hit its new high (after the July revaluation) only recently, the market felt it wouldn't reach a new record again in such a short period," said a dealer with a major foreign bank.
"On the other hand, the anticipation of a US decision to go with another rate hike tonight helped the dollar to strengthen."
The US Federal Open Market Committee will meet on Tuesday and is expected to raise the benchmark Fed funds rate by 25 basis points to 4.0 percent.
That would be the 12th consecutive increase.
Domestically, the Chinese currency firmed against the euro to close at 9.6867 compared with 9.7469 on Monday, and strengthened to 6.9309 per 100 yen from 9.9826, the central bank said on its Web site.
It had taken the yuan more than three months to rise 0.3 percent, or the daily limit set for the currency to rise or fall as laid out during the July 21 revaluation.
Dealers expected the yuan's slide against the dollar to continue in coming days should the greenback hold steady.
Over the longer term, however, a gradual and upward movement was inevitable, given China's strong economy and strong capital inflows, economists say.
One-year onshore yuan forwards were quoted at 7.84 to the dollar on Monday, indicating the market believes the yuan will be 3 percent firmer in a year's time.