We successfully grow the Pb(100) thin films on the substrate of Ge(100) by using Au/Ge(100)-c(2x8) reconstructed surface as a template at T=-150℃. Through the thickness dependence of quantum-well-state energies measured by photoemission spec- troscopy, we found the Pb(100) thin film grow layer-by-layer. By checking the Low Energy Electron Diffraction (LEED) pattern, we observed that the square structure of Pb(100) thin film trans- forms to a hexagonal structure after being annealed to room temperature, but the size of the special hexagonal lattice was different from that Pb(111) films.