The Denmark international moved to Villa Park in June last year but failed to secure a regular place in Paul Lambert's squad in his first season at the club.
Having made just six appearances for Villa, scoring once, Helenius will spend next season on loan with the Superliga outfit.
During his last season in Denmark, Helenius scored 16 goals in 33 league games, although Aalborg coped well without him as they lifted the title last term.
"It has recently been a dream for me to return home to AaB and I am extremely pleased that it has fallen into place," Helenius told the Danish champions' official website.
"I know the style of play... and I look forward to again being part of the AaB squad, where I can contribute with goals and assists."
Helenius scored 40 times in 102 matches for the Danish club before moving to Villa.
