Nanofibers of phenylsilsesquiazanes (SSQZ), as a precursor of inorganic silicon nitride nanoweb, was prepared using the electrospinning process. The SSQZ was prepared by ammonolysis of phenyl trichlorosilane and condensation of the resulting aminosilanes. The molecular weight of resulting SSQZ increased with initial concentration of phenyl trichlorosilane, reaching plateau above 20wt% of the silane. When the SSQZ was electrospun alone, it did not form fiber even with 20wt% concentration of SSQZ. However, it was possible to prepare fibers by adding poly(ethylene oxide) (PEO) as a viscosity enhancer. The diameter the of electro spun fibers was modified by the total polymer content and the content of PEO. The best result was obtained when the total concentration of the polymer was in the range of 15 to 20 wt% while the SSQZ/PEO ratio was 95/5.