That toppled China's trade-sensitive yuan from a six-month peak and lifted the yen from a seven-month trough. But moves in morning trade were slight as markets wait to see the deal inked.
"The deal is priced in," said National Australia Bank's head of FX strategy, Ray Attrill. "I can't see any reason why the yuan should continue to strengthen, given the limited amount of tariff rollbacks that are contained in this deal."
The yuan is the currency most sensitive to Sino-U.S. trade relations, and it retreated 0.2% to 6.8990 in offshore trade.
The yen was nearly 0.1% firmer at 109.91. The euro was steady at $1.1129 and the Swiss franc held on to overnight gains to sit at 0.9672 per dollar.
The trade-exposed Australian and New Zealand dollars each eased by 0.1%, with the Aussie last at $0.6895 and the kiwi at $0.6606. Against a basket of currencies the U.S. dollar held at 97.372.
U.S. President Donald Trump is slated to sign the trade agreement with Chinese Vice Premier Liu He at the White House at 1630 GMT.
Washington has agreed to suspend tariffs on $160 billion of some Chinese-made electronics, and to halve existing tariffs on $120 billion of other goods to 7.5%.
A source told Reuters that China has pledged to buy almost $80 billion of additional manufactured goods from the United States over the next two years under the deal, although some U.S. trade experts called that unrealistic.
Mnuchin said deal documents will be released on Wednesday.
Elsewhere the British pound GBP= trod water at $1.3023, ahead of inflation data due at 0930 GMT.
The consensus expectation is for core annual inflation to hold steady at 1.7%. However several recent hints at rate cuts from Bank of England policymakers have investors on edge that a miss on the downside may strengthen the case for monetary easing.
Money markets are now pricing in a 43% chance for a 25 basis point cut in rates at the end of this month.
"If we saw core inflation coming in at say, 1.4%, then I think that would inflame the situation," said Chris Weston, head of research at Melbourne brokerage Pepperstone.
He added that business surveys next week would be even more closely watched. "If they don't show any kind of meaningful rebound, then you're probably going to get a market that's pricing in (the chance of a cut) at north of 50%."
(Reporting by Tom Westbrook; editing by Richard Pullin) ((email@example.com; +65 6318 4876;))