"It hasn't been papered yet but it is being papered," Trump told reporters at the White House.
He reiterated that China committed to greater purchases of US farm exports, and made concessions because of economic pressure by Washington.
"They want to make a deal. They have to make a deal. Their economy has been hurt very badly by what we've done and the tariffs," Trump said.
Markets rallied Friday as the deal was struck, in relief after the steady escalation in the trade conflict with China.
Last week, Trump hailed a breakthrough on a "phase one" deal that he said was substantial and included a surge in purchases of American farm products and also covers intellectual property, financial services and currencies.
However, comments from officials in Beijing raised skepticism about the significance of the agreement.
While the deal meant tariffs increases planned for this week would not go forward, it did not roll back any of the stinging import duties imposed up to now on hundreds of billions of dollars in trade between the economic powers, nor did it address another round of import taxes planned for December.
Scant specifics are available but Trump says he hopes to sign the agreement with Chinese President Xi Jinping at the APEC summit in Chile next month.
The partial trade bargain struck last week with China is now being formally put down in writing.