A sulfonatocalixarene tanning agent for leather tanning and a preparation method comprises: using resorcinol and aldehyde monomers as raw materials for the tanning agent; adding an ethanol solution into the resorcinol, dropwise adding an inorganic strong acid catalyst and aldehyde derivatives, heating to react, cooling, carrying out suction filtration, repeatedly washing with ethanol and distilled water, and drying to obtain resorcinol calixarene; and weighing the resorcinol calixarene, and adding a sulfonating agent to react, thereby obtaining a sulfonatocalixarene tanning agent aqueous solution.