Highly c-axis oriented YBCO thin films have been grown on MgO substrates by laser ablation. A Nd:YAG laser was used to fabricate YBCO thin films. The wavelength of the laser can be chosen among 355 nm, 532 nm, and 1064 nm. By varying the thickness and the film deposition temperature of the thin films, we observed the changes of the film orientations. We can get highly c-axis oriented double-sided YBCO thin films by optimizing the thickness and the deposition temperature of YBCO thin films. The thin films were systematically investigated using Raman spectroscopy and X-Ray diffraction to ensure the relation between the orientations and the thickness of the thin films.