The invention discloses a preparation method of high-temperature resistant superparamagnetic tin dioxide coated iron oxide nano materials, comprising the following steps: mixing the tetraphenyltin and monodispersed iron oxide nano materials according to the mass proportioning of 4-20:1, adding solvent, preparing 4.3 mmol/L-430 mmol/L of tetraphenyltin solution, placing the reaction solution in a container, heating to 260 DEG C to 310 DEG C, reacting for 2h-48h, centrifuging, washing and drying the obtained product to obtain the solid powder. The invention can lower reaction cost, improve the production efficiency of tin dioxide coated iron oxide nano materials; and the prepared nano composite materials have superparamagnetism, high thermostability and good repeatability.