1D SiC materials have attracted much attention because of the high strength and modulus, low density, excellent oxidation resistance and chemical stability. In this work, flexible SiC nanofiber mats with designable components and structure were successfully fabricated by electrospinning and high temperature treatment using polycarbosilane (PCS) as precursor. In the process of high temperature pyrolysis, SiC nanowires with the diameter of 100 ~ 200 nm were in-stu grown on the surface of continuous SiC nanofiber (~ 500 nm) without any catalyst. The hierarchical structure dramatically improved the specific surface area of SiC nanofiber mat from 131.1 m2/g to 396. 8 m2/g. After bending over 1000 times, the SiC nanofiber mat remained undamaged, showing good flexibility and bending resistance. Moreover, the SiC nanofiber mat shows super hydrophobic and oleophilic properties. The SiC nanofiber mat with multi-scale structure exhibits great potential to be applied in harsh environment as catalyst support and water treatment template material.