The invention relates to a chromium-free waterborne corrosion resistant coating for the surface of metal and a preparation method thereof. The chromium-free waterborne corrosion resistant coating comprises the following components in percentage by mass: 15-33 flaked zinc powder, 2.5-8 flaked aluminium powder, 13.5-24 solvent, 0.2-2.5 assistant, 14-22 first silane coupling agent, 2-6 second silane coupling agent, 0.05-1.5 nano SiO2,0.03-1.2 nano TiO2, 0.02-1.5 nano ZrO2, 0.3-1 silver salt, 0.1-0.3 polyaniline, 0-0.6 tackifier and the balance of H2O, wherein the first silane coupling agent is a bi-[Gamma-(triethoxysilane) propyl] tetrasulfide; and the second silane coupling agent is a Gamma-aminopropyltriethoxysilane or Gamma-methacryloxypropyl trimethoxysilane. The coating contains no chromium and has corrosion resistance according with an international newest metal surface corrosion prevention technology.