The invention discloses a pomegranate-like structured composite material preparation method which comprises the following steps: S1, taking a polyacrylonitrile solution, adding silica nanoparticles, and fully dispersing; S2, adding deionized water after stirring for emulsification to obtain a mud like precursor; S3, heating the mud like precursor obtained in the S2, and annealing to obtain a solid composite; and S4, grinding the solid composite obtained in the S3 into micron particles, adding a hydrogen fluoride solution for corrosion for a certain period of time, washing hydrogen fluoride, and drying to obtain a pomegranate-like structured composite material. According to the method, polyacrylonitrile is used for coating the silica particle surface, the polyacrylonitrile is emulsified when meeting water, so that the coated silicon particles are agglomerated, the coated silicon particles are carbonized and ground for formation of the pomegranate shaped structured silicon carbon composite material, HF is used for direct corrosion of the silicon nanoparticles in the material for preparation of the hollow pomegranate-like structured composite material, and detailed structure characterization and electrochemical performance testing of the material show that the material is good in performances.