The invention discloses a super-hydrophobic/oleophylic porous mesh film for oil-water separation and a preparation method and application thereof. The preparation method comprises the steps that firstly, the porous mesh film is cleaned and then is blow-dried with nitrogen, and water solutions of polycation electrolyte, sodium sulphide and copper nitrate are prepared; then, the cleaned mesh film is soaked in the polycation electrolyte water solution, taken out for washing, then is soaked in the sodium sulphide water solution, taken out for washing, finally soaked in the copper nitrate water solution and taken out for washing, and the process is repeated; finally the obtained mesh film is put in a polydimethylsiloxane solution and is taken out, heated and cured to obtain the super-hydrophobic/oleophylic porous mesh film. The preparation method is simple, reaction conditions are mild, no expensive fluorine-containing reagent is needed, the costs are low, and the super-hydrophobic/oleophylic porous mesh film can be suitable for multiple different substrates and large-scale production. The obtained mesh film is non-toxic and harmless, oily wastewater separation can be quickly and efficiently achieved, and meanwhile the mesh film has good stability and can achieve multiple times of recycling.