The invention relates to a wear-resistant hydrophobic nano composite film and a preparation method thereof, belonging to the technical field of metal surface treatment and modification. The composite film is based on high-speed steel, or titanium alloy, or hard alloy, or pure metal, and a pure metal film and a microstructure nano composite film are sequentially prepared on the base surface. The preparation method comprises the following steps: depositing a nano composite hard film with excellent mechanical properties on the base material surface by arc ion plating, and generating a micro/nano dual structure on the film surface by an ultra-fast laser processing technique to obtain the surface film with favorable mechanical properties and certain hydrophobicity. The film maintains excellent mechanical properties of the nano composite hard film: high surface hardness, high toughness, high wearability and high scratch resistance; and the microstructure on the film surface is constructed, so that the film has certain hydrophobicity. The preparation method has the advantages of simpler equipment, low cost, low energy consumption and no pollution, and can implement efficient green manufacturing.