In the past decades, nanowires attracted lots of attentions due to their unique properties, so they are predicted to be the candidates for nano-devices in the next generation. Among nano-materails, titaninm dioxide is a well known photocatalyst, which possesses excellent photoelectric transformation efficiency. Alumina is a common gate oxide material with high dielectric constant (k) and low leakage current. We coated a extremely thin sheath of titaninm dioxide on the surface of alumina nanowire by atomic layer deposition (ALD). From the selected area electron diffraction (SAED) image and energy dispersion spectrum (EDS) results by TEM, structure and composition of the nano-composite was identified to be single crystalline γ-alumina and titanium oxide. An exceptional epitaxy effect of ALD on alumina nanowire was found by HR-TEM analysis. The effect may be resulted from the high crystallinity of Al2O3 nanowires and minimization of lattice distortion energy. C-V curve under light emission was also measured to discuss the feasibility of photocatalytic characteristics and carrier density of TiO2/Al2O3 nano-composite materials. The described fabrication and characterization technique enables a systematic investigation of the characteristic of capacitance in the nanowires as well as of the quality of the nanodevices.