Y2O3 thin films were deposited by reactive sputtering of Y target in Ar and O2 gas mixture. Residual stress was measrued by sin2$psi$ method of x-ray diffraction (XRD) and growth orientation was examined by measuring the relative intensity of (400) plane and (222) plane of Y2O3 films. In the case that Y2O3 films were deposited at 40$0^{circ}C$ and at low working pressure below 0.05 torr the film had large compressive stress and (111) plane orientation. At working pressure of about 0.10 torr the film had small compressive stress and (100) orientation. Above working pressure of 0.20 torr, the films had nearly zero stress and random orientation. In the case that the (111) oriented film deposited at low working pressure below 0.05 torr, as substrate temperature decreased, (111) orientation increased. In the case the film, with (100) orientation, deposited at working pressure of about 0.10 torr, (100) orientation increased with decresing substrate temperature. These relationship of residual stress and growth orientation can be explained by the relationship of surface energy and strain energy.