The structure of potassium hexatitanate (K2Ti6O13) nanowires has been investigated using both the Rietveld powder diffraction profile fitting technique and high resolution transmission electron microscopy (HRTEM) image simulations.From the Rietveld analysis it was shown that the nanowires had a monoclinic structure of the space group C2/M and the lattice parameters were a=1.5582 nm, b=0.382 nm, c=0.9112 nm. HRTEM conclusions agree with refinement results obtained from experimental XRD data. The good agreement between the experimental and simulated images confirms that the nanowires is indeed K2Ti6O13 nanowire. The growth axes of nanowires were mainly along the [010] direction.