Aluminum-doped zinc oxide (AZO) thin films with preferential c-axis orientation were obtained on float glass substrates (25 mm x 76 mm x 1 mm) by sol-gel dip-coating technique. Experimental results showed that annealing treatment influenced the c-axis growth orientation of AZO thin films dramatically. Optical and electrical properties and microstructures of AZO thin films had been investigated systematically. The transmission spectra of the films demonstrated that the transmittance was higher than 90% in the visible region, and the four-point probes technique measured the minimum resistivity of the films as 17.4 center dot cm. Room-temperature photoluminescence spectra indicated that AZO film had a broad emission peak at about 394 nm. Annealing treatment can enhance the ultraviolet emission of AZO thin films.