The superconducting properties of YBa$_{2}$Cu$_{3}$$O_{7-x}$(YBaCuO) thin films prepared by laser ablation have been investigated. The x-ray diffraction patterns of the films were substantially different from one another. The Y and Ba oxides are formed by the collisions with oxygen molecules. On the other hand, the Cu oxide is mainly formed at initial stage of the laser irradiation. The YBaCuO films manufactured on MgO(100) substrate were indicated T$_{c}$(zero)=90 K, T$_{c}$(onset)=92 K, and J$_{c}$=3.5*10$^{5}$ A/cm$^{2}$(at 77.3K). The optimum conditions were found to be a substrate temperature of 710.deg. C, an energy density of 2 J/cm$^{2}$, and a target-substrate distance of 60mm in an oxygen partial pressure of 200 mTorr.0 mTorr.