Abstract: A two-step anodization process was used to prepare highly-ordered porous anodic alumina（PAA）template.Titania nanowire arrays were prepared by the sol-gel/decompression method within the pores of anodic alumina template.The phenomenon of the sol filling into the template pores under different compressive stresses was particularly studied.It was showen that a certain decompression condition facilitated expulsion of the gas out of the PAA pores.Consequently，the degree of sol filling was very high and the prepared nanowires had good quality.Scanning electron microscopy（SEM）and X-ray diffraction（XRD）were used to characterize the morphology and phase structure of the template and nanowires.It was demonstrated by SEM that the nanowires were parallel to each other.The surface was smooth and there was no crack.The diameter of nanowires was about 50 nm.The center to center distance of nanowires were about 50 nm.The length and diameter of nanowires were consistent with the thickness and hole diameter of the PAA.So the growth of nanowires was dependent on the PAA template.It was demonstrated by XRD that the crystal constitution of the PAA was single θ-Al₂O₃ and the nanowire was anatase.