This invention discloses a descaling apparatus for steel tubes of the building scaffold, belonging to the technical field of construction equipment, which solves the existing problems with low quality in rust-removal of the steel tube of the building scaffold, and the descaling apparatus for steel tubes of the building scaffold comprises a bottom panel (1), a working table (11), a pushing base (2) on the bottom panel (1) along a length direction, several of forward rust-scraping rings (3) and several of reverse rust-scraping rings (4) on the working table (11), several of forward scrapers (33) on the forward rust-scraping rings (3), several of reverse scrapers (43) on the reverse rust-scraping rings (4), a driving member on the working table (11), several sets of rolling assemblies (5) on the working table (11); this invention has a better rust-removal effect and is more labor-saving when in manual operation.