The invention provides a new method for preparing a hydrophobic material. The method comprises following steps: firstly, surface micro / 
nano porous structural preparing, wherein a workpiece subject to conventional pretreatment is cleaned for standby application, the arc treatment technology is adopted for obtaining a roughening micro / 
nano porous surface on the surface of the workpiece; secondly, hydrophobic treatment(fluoroalkyl 
silane modification treatment), wherein a sample subject to arc treatment is immersed in a fluoroalkyl 
silane isopropyl alcohol solution, the sample is taken out and is naturally dried under the 
room temperature condition, and the superhydrophobic surface can be obtained. 
Arc welding is used for generating the strong and durable gas 
discharge phenomenon between the workpiece and two electrodes of a 
welding rod so as to form the micro / 
nano porous surface, meanwhile, in combination with the fluoroalkyl 
silane low-
surface energy substance, modification is carried out, two general methods are combined together, a new thinking is provided for preparation of the high-performance hydrophobic surface, and the new preparing method has the beneficial effects of being energy-saving, rapid, low in cost, low in preparing environment requirement, easy to operate and the like.