The two, along with a third man were indicted in October on charges of illegally copying music CDs, as well as Symantec computer security software and Adobe Systems Photoshop.
This is "the largest case involving CD manufacturing piracy uncovered in the United States to date," Ryan told a news conference. "The theft associated with this kind of piracy, copyright infringement, is in the hundreds of millions of dollars, I believe, on a yearly basis."
He said officials had seized nearly 500,00 pirated CDs and 5,500 stampers used to make the bootleg products. Many of the disks had FBI anti-piracy seals.
Each of the five counts against the men -- which include copyright infringement, trademark violations and trafficking in counterfeit labels -- carries a maximum prison sentence of five years. Ye and Hao will be sentenced at a later date. Zhai, who did not plead guilty, is due to appear in court in May.
Music industry officials say piracy has lead to a steady decline in CD sales in recent years. Overall U.S. music sales fell 0.6 percent to $12.27 billion in 2005, according to the Recording Industry Association of America.