The ruling from the WTO's appellate body on Friday said the EU isn't complying with international commerce rules by imposing anti-dumping duties on the fasteners from China.
The WTO ruled the EU's single duty requirements and practices are discriminatory and violated WTO rules.
It said the EU isn't calculating them fairly as it takes China as a single exporter, instead of treating the companies individually.
For a long time, the EU has been requiring Chinese exporters to prove they meet with the "single duty" requirements in responding to anti-dumping cases.
The EU imposed anti-dumping duties of 26.5 to 85% on fasteners from China for five years in January 2009.
China is the world's biggest producer of screws, nuts, bolts and washers, while the EU is its major market.
The WTO set up an expert panel on October 23, 2009 after China initiated the WTO case on July 31, 2009, saying anti-dumping measures taken by the EU against the import of Chinese steel fasteners violated WTO trade rules.
The WTO ruled on December 3 last year that the EU anti-dumping duties are discriminatory and violate global commerce rules.
The EU appealed on March 25 this year. China appealed further on March 30 on the remaining problems that did not win support from the expert panel. -- Source: ChinaDaily