The invention discloses a preparation method of a super-hydrophobic modified nanofiber membrane. The preparation method comprises the following steps: mixing a hydrophobic high polymer, electrolyte and a solvent A to obtain high polymer spinning solution, and carrying out electrostatic spinning, so that a nanofiber membrane is obtained; dispersing carbon nanofibers and nanocarbon particles into a solvent B to respectively obtain carbon nanofiber dispersion and nanocarbon particle dispersion, sequentially coating the nanofiber membrane, and drying, so that a precursor is obtained; and finally carrying out hot pressing, so that the super-hydrophobic modified nanofiber membrane is obtained. The invention discloses the preparation method of the super-hydrophobic modified nanofiber membrane, a number of nodes are avoided from being produced as the nanoparticles are directly doped into electrostatic spinning solution, the method is simple and convenient, the prepared modified nanofiber membrane has good hydrophobic property and is high in porosity, high in flux and extremely high in retention rate, and membrane requirements in a membrane distillation process are met.