UFC superstar Mark Hunt says he's "fine" with fighting until he dies ... but he's calling for it happen in a sport free of steroid users. 

"I will probably end my life fighting," Hunt wrote in a piece for The Players Voice. "If I die fighting, that’s fine. I just hope that if it does happen, it will be in an honest and fair competition."

The timing of Hunt's article probably ain't a coincidence ... released just after results from Jon Jones' B sample drug test -- confirming the presence of anabolic steroid Turinabol -- were made public

Mark's fought several fighters who've gotten popped for PED use -- most notably, Brock Lesnar at UFC 200. The Super Samoan called Brock's win "pre-meditated assault" ... and wants to make sure that doesn't happen to him, or anyone else, in the future. 

"I’ve fought a lot of drug cheats and copped a lot of punishment from guys who were cheating and that’s not right. The cheats get all the advantages."

Hunt says he accepts the damage he's taken throughout his career -- which he claims has led to slurred speech and lost memories -- but he's PISSED that cheaters may have prevented him from becoming a UFC champ.

Mark says his next contract is gonna have a clause where he gets all the money made by any opponent caught doping -- "That could be part of my legacy."