In a call with Secretary of State Marco Rubio, Wang spoke weeks before Donald Trump's 14-15 May Beijing visit to meet Xi Jinping.
China said Taiwan was the biggest risk point in bilateral ties and urged Washington to honour its commitments while preparing for high-level interactions and expanding cooperation.
The sides also discussed the Middle East as China, a key partner of Tehran, has kept some distance after Trump's joining Israel's attacks on Iran sent oil prices higher.
With a trade war looming, can the Trump-Xi summit secure a deal on both tariffs and Taiwan?
As the US reshores its chip industry, how will China use its supply chain power to retaliate?