Five members of Congress will visit until Monday, said Washington's de-facto embassy in the capital Taipei.
China launched its largest-ever military exercises around Taiwan after Ms Pelosi's visit earlier in August.
Beijing sees the self-governing island as its own, renegade territory that must be reunited with the mainland.
It believes that mission could be necessary with force, if other attempts at unification are unsuccessful.
Ms Pelosi became the most senior American politician to visit the island in 25 years during her appearance earlier this month.
Her brief, but controversial, stopover was labelled "manic, irresponsible and irrational" by the Chinese foreign minister.
Speaking during a meeting of south-east Asian foreign ministers in Cambodia, Wang Yi insisted that Taiwan would "eventually return to the embrace of the motherland".
Beijing continues to carry out military drills near the island. Earlier on Sunday, Taipei said it had detected 22 Chinese aircraft and six naval ships in and around the Taiwan Strait.
At the height of China's military exercises, Taiwan accused its neighbour of trying to change the status quo in the region.
On Sunday, its foreign ministry published photos of members of the US congressional delegation being greeted at an airport.
A statement from the American Institute in Taiwan said the team's visit was part of a wider visit to the Indo-Pacific region.
It added that the five members - led by Democratic Senator Ed Markey - would discuss issues including regional security, trade and investment with Taiwanese leaders.
The group are due to meet President Tsai Ing-wen on Monday.
President Tsai's office said the month's second high-level American visit signalled "firm support" for Taiwan.
The US does not officially recognise Taiwan - only a few countries do - however, it does maintain a strong relationship with the island, which includes selling weapons for Taiwan to defend itself.