The surface modification of sand in desert was studied and applied to the separation of oil-water mixture. The nano-silver rough surface was constructed with sand as substrate by layer-wise self-assembly method, and then modified by dodecyl mercaptan, to show superhydrophobic and superlipophilic properties. The surface morphology, wettability and oil-water separation performance of superhydrophobic and superlipophilic sand were characterized by low vacuum scanning electron microscopy, contact angle measuring instrument and separation efficiency, respectively. The surface of the modified sand was loaded with a "papiloid" nanometer silver layer. The contact angle of water on the surface was up to 156°±1°, while the contact angle of oil was 0°, showing good superhydrophobic-superlipophilic properties. Making use of the opposite wettability of sand surface for water and oil, not only can selective separation of heavy oil under water and light oil on water can also separate of emulsion from oil and water efficiently, and separation efficiency for different types of oil and water mixture is over 95.6%, after 20 successive separation, separation efficiency has no obvious changement, showing excellent recycling. After soaking in strong acid, strong alkali and NaCl solutions for 24 h and heating at different temperatures from 60~300 ℃ for 1 h, they showed good superhydrophobic properties.Loading with nano-silver crystals on the surface of sand by self-assembly method, and then use dodecyl mercaptan for surface grafting, the superhydrophobic sand obtained can not only separate the oil-water mixture with obvious interface, but also separate the emulsion formed by oil and water. After continuous separation, the separation efficiency is not significantly reduced. The related research is expected to provide a new idea for the extensive utilization of sand and the preparation of wastewater treatment materials.