Percival has made himself a key member of the Warriors pack since rejoining the club last year for his second spell.
Warriors coach Richard Hill revealed his delight at having Percival as part of his squad for the forseeable future.
"We're delighted that Percy has signed a new contract at Warriors because he is a key player for us both now and going forward over the coming years," Hill said.
"He has been a fantastic acquisition and has a superb attitude. He is extremely passionate about the club, having been here before, and he is one of the senior players who will drive the ambition of the club.
"Percy joined us from Harlequins because he wanted to see Worcester climb up the league and be successful. He is determined to see that journey through."
Warriors visit Exeter Chiefs on Saturday.