EXCLUSIVE

Dr. Dre -- who just made a fortune selling off Beats headphones -- wants to stop cheap, Chinese-made knockoffs from jacking his reputation ... so his company is suing alleged counterfeiters for what could easily be BILLIONS of dollars!

In the lawsuit, Beats claims a nefarious group of unnamed websites based in China ... are getting filthy rich selling cheaply-made, counterfeit headphones, bearing the red "b" logo -- and raking in more than $135 BILLION in revenue.

Beats points out it's the headphone of choice for Lady Gaga, Justin Bieber, Diddy and tons of other celebs ... according to the lawsuit, obtained by TMZ -- so it has a vested interest in protecting its trademark.

Beats is suing to stop all sales of the forgeries ... and to take over all of the domain names used by websites hawking the fakes.