The utility model discloses a be used for reinforced (rfd) supporting platform device of big steel form of outer wall, including a plurality of support frames, each support frame is fixed side by side on structure of external wall, the support frame is including the type of falling L support and baffle, and short channel -section steel welding forms the type of falling L support with the level by perpendicular long channel steel, and it has the set -square to weld to the side of overlapping department of perpendicular long channel steel and the short channel -section steel of level, keeps away from one of set -square on the level weak point channel -section steel and serves skin weld and have baffle, baffle perpendicular to level weak point channel -section steel, perpendicular long channel steel goes up to open has the bolt hole, and the type of falling L support passes the bolt hole through the king -bolt and fixes on structure of external wall, the upper surface of the short channel -section steel of level of overlapping department of perpendicular long channel steel and the short channel -section steel of level supports there is the big steel form of outer wall. The utility model provides an outer wall with unsettled difficult problem of establishing of big steel form, can effectively support and use big steel form with fixed outer wall, has improved the outer wall and has established the quality with propping up of big steel form, the result of use is good.