The commerce ministry says the investigation will take a year but could be extended by six months.
China's commerce ministry has said it had launched an anti-dumping investigation into imports of an important engineering chemical from the European Union, the United States, Taiwan and Japan.
Beijing said on Sunday it would probe imports of polyoxymethylene copolymer, a thermoplastic used in everything from phones, car parts, and medical equipment.
The probe follows a number of similar investigations by the EU into China's subsidies for its industry.
Last month, the bloc launched a probe into China's medical devices market over alleged unfair procurement practices.
Beijing said the probe amounted to "protectionism" and warned it would harm the EU's image.
It also follows sharp hikes in US tariffs on Chinese imports like electric vehicles and semiconductors.
