Ultrafine tin oxide (SnO2) fibers having a rutile structure, with diameter ranging from 100 nm to several micrometers, were synthesized using electrospinning and metallorganic decomposition techniques. In this work, we propose a precursor solution that is a mixture of pure SnO2 sol made from SnCl4:H2O:C3H7OH:2-C3H7OH at a molar ratio of 1:9:9:6, and a viscous solution made from poly(ethylene oxide) (PEO) (molecular weight 900000) and chloroform (CHCl3) at a ratio of 200 mg PEO/10 mL CHCl3. This solution allows to obtain an appropriate viscosity for the electrospinning process. The as-deposited fibers were sintered at 400 degrees, 500 degrees, 600 degrees, 700 degrees, and 800 degrees C in air for 2 h. Scanning electron microscopy, scanning probe microscopy, X-ray diffraction, Raman microspectrometry, and X-ray photoelectron spectroscopy (XPS) were used to characterize the sintered fibers and elucidate the chemical reaction during sintering. The results showed that up to the sintering temperature of 700 degrees C, the synthesized fibers are composed Of SnO2. XPS was found to reflect the complicate chemical changes caused by the sintering process.