A heel block structure of retaining wall is provided to attain structural stability and excellent application property since the retaining wall block structure is assembled at a construction site directly. A heel block structure(100) of retaining wall comprises a retaining wall block(110), a T-shaped block(120) uniting between the insertion groove of the retaining wall block and insertion hole of the adjacent it puts retaining wall block and forms the heel block body, a plurality of fixing blocks(130) which unites between the T-shaped block and adjacent T-shaped block and fixes, and a rubble(140) filled with the rear portion of the retaining wall block and adjacent positioned two T-type blocks and the internal space formed owing to the fixing block.
