Both houses of Congress backed the bill, which also includes measures against Iran and North Korea, but it was thought Mr Trump might veto it.
White House spokeswoman Sarah Huckabee Sanders said Mr Trump would sign the bill, but only after having negotiated "critical elements" of it. She did not specify what those elements were.
"He has now reviewed the final version and, based on its responsiveness to his negotiations, approves the bill and intends to sign it," she said.