The "Hong Kong Autonomy Act" passed by unanimous consent. To become law, it must also pass the House of Representatives and be signed into law by President Donald Trump.
Democratic Senator Chris Van Hollen, a lead sponsor, said in the Senate the legislation would send a clear message to Beijing that there would be consequences if it acts to undermine Hong Kong's autonomy.
"This could be our last opportunity to stay Beijing's hand before it destroys what is left of freedom in the city," said Republican Senator Josh Hawley, another sponsor.
The bill almost passed earlier this month, Van Hollen said, but was blocked by Republican Senator Kevin Cramer – who had co-sponsored it – at the request of the Trump administration, which made a late request for technical corrections.
The delay underscored how complicated it can be to pass legislation pushing back on China, as the administration pursues a trade deal with Beijing and the two powerful countries grapple for international influence and clash over human rights.US-China relations have reached their lowest point in years since the coronavirus pandemic, which began in China, hit the United States hard.