The work aims to study stability of hydrophilic surface wettability as a function of aging temperature by preparing micro-nano structures and realizing super-hydrophilicity on the surface of 304 stainless steel by chemical etching and chemical oxidation. An etching solution was obtained by mixing 2 mol/L FeCl3 solution, HCl and H2O2 in a volume ratio of 15:1:1. Contact angle, micro-nano surface morphology and surface elements of the sample were characterized with contact angle measuring instrument, field emission scanning electron microscope and self-contained energy dispersive spectrometer, and change rule of wettability in different treatment conditions was analyzed. The super-hydrophilic surface could be obtained by chemical etching and chemical oxidation on the 304 stainless steel substrate with intrinsic wetting angle of 45°. Super-hydrophilicity of the sample could be maintained for a certain period of time at normal temperature. Wettability of the super-hydrophilic surface changed after aging treatment at high temperature, and the super-hydrophilicity was recovered after aging treatment at 400 ℃. The method facilitates preparation of micro-nanostructure on stainless steel surface of corrosion resistant substrate, and has effects on wettability of substrate surface.