The invention relates to dendronized alcoxyl ether polymer, modified gold nano microspheres thereof and a preparation method thereof. The gold nano microspheres are prepared by enabling the dendronized alcoxyl ether polymer with trithioester at the terminal to act with the surfaces of gold nanoparticles to form gold-sulfur bonds. The temperature-sensitive dendronized gold nano microspheres have the advantages of nanoscale and good monodispersity, a single microsphere can show temperature sensitive behaviors like quick dewatering collapse along with temperature rise, size of the microspheres becomes small, and the process is reversible. The surfaces of the temperature-sensitive dendronized gold nano microspheres contain large-size dendronized alcoxyl ether polymer, so that the microspheres have high capacity of loading micromolecular compounds and good biocompatibility, thereby having potential application value in the fields of biomedical materials, intelligent photoelectric materials and nano containers.