In response to a 2012 complaint, the WTO said the US improperly imposed tariffs on Chinese steel and solar panels.
In a separate ruling, it said the US must change the way it imposes tariffs on India steel products.
The US is embroiled in several trade spats with China and India.Complaints
"China urges the United States to respect the WTO rulings and correct its wrongdoings of abusively using trade remedy measures, and to ensure an environment of fair competition for Chinese enterprises," said China's foreign trade ministry in a statement.
However, the WTO did not agree with all of the complaints filed by India and China.
The US - which has argued it imposed the tariffs to combat artificially low prices on products from India and China's state-subsidised industries - has the right to appeal the ruling.