The invention discloses a foldable moving building 3D printing system comprising a pair of transverse folding rails. Vertical telescopic uprights are mounted on the transverse folding rails correspondingly; after the transverse folding rails are unfolded, the vertical telescopic uprights can slide on the transverse folding rails; a telescopic cross beam is mounted between the pair of telescopic uprights; a telescopic material extruding printing head capable of sliding along the telescopic cross beam is assembled on the telescopic cross beam; and a bottom plate power device is mounted at the bottom of each transverse folding rail. According to the foldable moving building 3D printing system, the modularized design and folding moving are adopted, the transportation efficiency and space of the printing system are increased, and accordingly the construction cost is saved.