Djulbic, 31, played for Glory between 2007 and 2009, before spells with Rot Weiss Ahlen, Gold Coast United and Guizhou Renhe. His last club was Al-Wahda of the United Arab Emirates Pro League.
A two-cap Australia international, centre-back Djulbic will bolster Perth's defensive stocks with marquee international William Gallas tipped to leave the club
"It's great to be back at Glory, the club where I made my professional debut and which has given me so much, both on and off the pitch," Djublic said in a statement.
"It's been over five years since I last played for Glory and I am looking forward to once again playing in the A-League. Next season is very important to me and all involved in the club. We have to compete and we have to get back to our winning ways. It's great to be home."