Chinese vice foreign minister Le Yucheng spoke to ambassador Branstad and urged the "US side to correct mistakes and change course."
Chinese foreign ministry in a statement said Yucheng told that US ambassador to "refrain from putting the bill into practice, and immediately stop interfering in Hong Kong affairs and China's internal affairs, so as to avoid further damage to China-US relations and bilateral cooperation in important areas."
The Hong Kong Human Rights and Democracy Act requires the US president to annually review Hong Kong's trade status. The US House in a unanimous vote had voted for the bill angering China.
Trump also signed legislation banning sales of tear gas, rubber bullets and other equipment which was being by Hong Kong police against protesters in the city.
China threatened "firm countermeasures" against the United States after President Donald Trump signed the Hong Kong democracy bill.
"The nature of this is extremely abominable, and harbours absolutely sinister intentions," the foreign ministry said in a statement.
While signing the bill, Trump said he "hoped the leaders and representatives of China and Hong Kong will be able to amicably settle their differences," while adding that he respected Chinese President Xi Jinping.
Meanwhile, Hong Kong police entered the Polytechnic University on Thursday at the end of a nearly two-week siege that saw some of the worst clashes between protesters and security forces.
Trump's move to sign the Democracy act comes amid the US-China trade war with the US president increasingly hinting that the two biggest economies are close to a deal after months of talks.