$alpha$-Sexithiophene ($alpha$-6T) thin films were deposited by organic molecular beam deposition (OMBD) technique. The $alpha$-6T was synthesized and purified by the sublimation method. The thin films of the $alpha$-6T were deposited under various deposition conditions. The effects of deposition rate, substrate temperature, and vacuum pressure on the formation of these films have been studied. The molecular orientation, crystallinity, and surface morphology of $alpha$-6T films were investigated with angle-resolved UV/visible absorption spectroscopy, X-ray diffractometry (XRD), and atomic force microscopy (AFM). It was found that the crystalline structure of $alpha$-6T films was monoclinic and independent uppon substrate temperature, deposition rate, and deposition pressure. On the other hand, the $alpha$-6T molecules in the film deposited at a low deposition rate, higher substrate temperature, and under a high vacuum tended to be aligned perpendicular to the substrate.