She is expected to have lunch and then leave the island, Taiwan's official central news agency says.
The trip, which is not backed by President Biden, is the first by such a senior US official in 25 years.
China's foreign ministry has summoned the US ambassador to protest about the visit - saying Beijing will not stand idly by.
China's army will hold military exercises in areas around Taiwan from Thursday until Sunday, its state media says.
But the US says there is no need to turn the visit into a crisis, with Pentagon spokesman John Kirby emphasising America supports the status quo.
Beijing sees self-ruled Taiwan as a breakaway province that will eventually be part of the country.