Beijing was reacting to a report by the US Treasury on Tuesday, which warned it could be labelled a manipulative trading partner unless it took steps towards scrapping the yuan's decade-old peg against the dollar.
The report triggered Washington to issue its toughest warning yet on China's rigid foreign exchange policy, which US manufacturers say undervalues the yuan by as much as 40% giving Chinese exporters an unfair advantage in world markets.
Chinese Commerce Minister Bo Xilai said Beijing was studying the Treasury's report, but it disagreed with its conclusions.
"I believe they are not reasonable," Bo said on Wednesday.
Bo also cried foul at moves by the United States and Europe to curb China's textile exports.
Washington last week decided to restrict imports of Chinese trousers, shirts and underwear. The European Commission stepped up the pressure on Tuesday, seeking emergency talks on T-shirts and flax yarn that could lead to curbs on imports into the EU.
Bo said Washington and Brussels had had 10 years, until the end of 2004, to phase out quotas on developing countries' textile imports.
"Regrettably, developed countries such as Europe and the United States failed to do so," he said. "They kept the vital part of 70 to 90% of quotas until the end of last year, which led to a temporary surge in Chinese textile exports early this year."