The 27-year-old Gambian international spent last season on loan at Turkish side Denizlispor and had a year left on his contract at the Madejski stadium.
Barrow scored 14 goals in 82 games for championship side Reading FC after joining from Swansea FC in 2017.
He joins a Jeonbuk side currently occupying second position in the South Korean K-League, with 26 points, three points off leader Ulas Hyundai who collected 29 points.
